LIBRARY OF CONGRESS. 



%»p. -"Inp^rigP !f».. 




A HAND-BOOK OF 



PRECIOUS STONES 



M. D. ROTHSCHILD 




NEW YORK & LONDON 

G. P. PUTNAM'S SONS 

&\}t ftnittarbockr $jrcss 

1890 



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COPYRIGHT BY 

M. D. ROTHSCHILD 



Ube Iftnicfeetbocfecr press, IRew Jgorft 

Electrotyped and Printed by 
G. P. Putnam's Sons 



CONTENTS. 



PAGE 

What are Precious Stones ? 7 
Physical Characters — 

Crystallization ...... 10 

Cleavage 10 

Fracture 11 

Optical Properties — 

Refraction . . . . . . 12 

Polarization of Light .... 13 

Pleiochroism ...... 14 

Colors ......... 15 

Lustre ........ 17 

Streak ......... 18 

Hardness ....... 19 

Specific Gravity ...... 21 

Weight 27 

Fusibility 28 

Magnetism ....... 30 

Transparency ...... 30 

Phosphorescence . . . . . . 31 

Electricity ....... 31 

Cutting and Polishing ..... 32 

Diamond ....... 35 

Corundum ....... 39 

The Ruby ....... 40 

Sapphire ....... 43 

Fancy Sapphires 44 

i 



CONTENTS. 



Star Sapphires 45 

Spinel 46 

Beryl . 50 

Emerald 51 

Beryl 53 

Chrysoberyl 54 

Cymophane . . . . . ..; 56 

Alexandrite 56 

Zircon 58 

Turquois 60 

Tourmaline 64 

Opal -. 69 

Pearl 71 

Chrysolite 78 

Garnet 80 

Topaz . . . . . . . .84 

Apatite : 87 

Felspar 88 

Moonstone ....... 89 

Sunstone (Avanturine Felspar) ... 90 

Amazon Stone (Green Felspar) . . . 91 

Labradorite ....... 91 

Cyanite ........ 93 

Lapis Lazuli ....... 94 

Hiddenite ....... 95 

Dichroite 97 

Idocrase 98 

Euclase ........ 99 

Sphene . 100 

Phenacite ....... 101 

Epidote 101 

Axinite 102 

Diopside 103 

Fluor Spar " 104 



CONTENTS. Ill 

PAGE 

Hypersthene 105 

Quartz . . . . . . . 106 

Crystallized Quartz ...... 109 

Amethyst . . . . . . . no 

Yellow Quartz . . . . . . in 

Cairngorm, etc. . . . . . . 111 

Rose Quartz . . . . . . . 113 

Avanturine . . . . . . . 114 

Cat's-Eye 114 

Crocidolite . . . . . . . 115 

Heliotrope . . . . . . . 116 

Chrysoprase . . . . . . . 117 

Prase 117 

Plasma 118 

Chalcedony . . . . . . . 118 

Agates . . . . . . . . 119 

Onyx or Agate Onyx . . . . . 120 

Carnelian . .* . . . . . 122 

Jasper 123 

False Lapis . . . . . . . 124 

Hematite . 124 

Obsidian . . . . . . . 125 

Malachite 126 

Jet 128 

Amber 128 

Coral 130 

Table of Hardness and Specific Gravity . . 132 

Index . 135 



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PREFACE. 

The object of this little book is to 
convey to the merchant, the workman, 
and the amateur, in a condensed and 
accurate form, information concerning the 
various properties of precious stones. Be- 
sides drawing freely on a number of au- 
thorities, the author has used his practical 
experience to indicate such tests as an 
amateur can readily make. Specific grav- 
ity, hardness, and dichroism are tests 
which are easily mastered, and a thor- 
ough understanding of these three prop- 
erties will assist in classifying doubtful 
gems. 

Such stones have been dealt with prin- 
cipally as are used in commerce for jewelry 
and ornamental purposes. 

5 



6 PREFACE. 

The attention of the writer has often 
been called to the general lack of knowl- 
edge among the jewelers regarding pre- 
cious stones other than diamonds, rubies, 
sapphires, and emeralds. 

As there are so many other beautiful 
and rare gems which nature yields to 
man, and which are worthy of the jew- 
elers' art, the author trusts that his book 
will awaken a new interest in the fascina- 
ting study of mineralogy as applied to 
precious stones, and that at some future 
day he may feel encouraged to enlarge 
upon this treatise. 

M. D. Rothschild. 

41 and 43 Maiden Lane, 
New York. 



HAND-BOOK OF PRECIOUS 
STONES. 



What are Precious Stones? 

The mineral to which the term " pre- 
cious stone " is applied, must be adapt- 
able for jewelry or ornamental purposes 
and must possess beauty, hardness, and 
rarity. 

The beauty of a precious stone or gem 
consists of its color or colorlessness, bril- 
liancy or softness of lustre, and transpa- 
rency. To take a high and lasting polish, 
a mineral must be hard, — and many stones 
that would otherwise be highly valued are 
low in the estimate of worth because they 
do not possess of sufficient hardness to 
make them endure the wear and friction 
7 



8 PRECIOUS STONES. 

to which a precious stone is subjected 
when used in the form of jewelry. The 
rareness of precious stones has a decided 
effect in determining their values. For 
instance, the crocidolite, commercially 
known as tiger-eye, was sold by the carat 
some years ago, and was largely used in 
the making of fine jewelry. To-day, this 
material is so plentiful that it is no longer 
classed among the higher gems, but serves 
for cameos and intaglios like chalcedony 
and onyx. 

The changes of fashion have much to 
do with determining the market value 
of precious stones. Amethysts, topazes, 
cat's-eyes, aquamarines, alexandrites, and 
even emeralds and opals have been 
eagerly sought for at times and then 
again neglected for other gems, causing 
a sensible difference in the value of these 
stones. 

There are all degrees of precious 
stones, from the valuable diamond and 



WHAT ARE PRECIOUS STONES? g 

corundums to the humbler quartz, ame- 
thyst, and topaz. 

It has been a mooted question as to the 
proper dividing line between stones that 
deserve the title " precious," and those 
which should be placed in a so-called 
semi-precious or lower category. To draw 
such a line is hardly possible, as neither 
hardness, rareness, nor value would be a 
positive test — some of the hard stones, 
like zircon and almandines being less valu- 
able than the softer opal, while the dia- 
mond, one of the most plentiful of precious 
stones, is at the same time, one of the most 
valuable. 

Neither can price be taken as a complete 
test, because fashion makes a turquois, an 
opal, or an emerald much more valuable at 
one time than at another. All precious 
minerals used for ornamental purposes, 
from the diamond to quartz, or chalce- 
dony, may properly be termed precious 
stones. 



lO PRECIOUS STONES, 

Physical Characters. 

CRYSTALLIZATION. 

Precious stones are found either in 
crystallized or amorphous conditions. The 
forms of crystallization are : 

i Isometric or Cubic ; having the axes equal. 

2 Tetragonal or Pyramidal [ having only the 

3 Hexagonal or Rhombohedral ) lateral axes equal. 

4 Orthorhombic or Trimetric ..)-,. ,-, 

5 Monoclinic or Oblique . . . j ™^ ^ '* 
o 1 nclmic or Anorthic . . . . j ^ 

Most precious stones crystallize, but the 
specimens that have the crystallization 
clearly defined are seldom found. The 
amorphous condition includes the turquois, 
opal, and obsidian, which minerals are 
found in masses or veins surrounded by a 
matrix. 

CLEAVAGE. 

Many minerals can be separated readily 
in one direction by simply making a small 
indentation with a harder mineral, then 
introducing the blade of a knife into the 
scratch and striking it a sharp blow, — this 
separates the crystal. There are certain 



FRACTURE, II 

planes at right angles where the crystal 
can be separated ; this property is called 
cleavage and the planes, cleavage planes. 

In some minerals cleavage is difficult to 
produce, while in others such as mica and 
rock-salt, cleavage is highly perfect and 
the number of separations produced is 
only limited by the thickness of the blade 
used in separating the planes. 

The property of cleavage is very useful 
and of great assistance to the lapidary, 
as it enables him to shape a diamond or 
other hard stone nearly to the size he 
desires, and at the same time to save the 
extra material cleaved off, which can be 
used for smaller gems, and which under 
other conditions would have to be ground 
away. 

FRACTURE. 

Fracture surfaces are the result of the 
breaking of a crystal otherwise than by 
cleaving, and in a different direction from 
the cleavage planes. 



12 PRECIOUS STONES. 

When the form of fracture is composed 
of concave and convex surfaces it is called 
conchoidal ; when free from inequalities 
it is known as even or smooth, and when 
covered by small splinters, splintery or 
uneven. 

Optical Properties. 

REFRACTION. 

When a ray of light passes from one 
medium to another, or from the air to a 
crystal it is bent or refracted ; this is called 
single refraction and takes place in the 
diamond, spinel, and garnet. 

Most of the other transparent precious 
stones possess double refraction — that is, 
the ray of light enters the crystal and 
divides into two parts, one following the 
ordinary laws of refraction, while the other 
part or extraordinary ray does not obey 
the usual law. 

There are precise methods for measur- 
ing the indices of refraction, but they are 
not applicable to polished gem stones. 



POLARIZATION OF LIGHT. 1 3 

POLARIZATION OF LIGHT. 1 

Polarization is a peculiar modification 
which, under certain conditions, a ray of 
light undergoes. This property is easier 
to observe than double refraction. 

If from a transparent prism of tourma- 
line two thin plates are cut, parallel to 
its axis, they will transmit light when 
they are placed above each other with 
the chief axis of each in the same 
direction. 

When one of the plates is turned at 
right angles to the other, no light, or but 
very little, is transmitted, so that the 
plates appear black. 

In passing through the first slip, the 
rays of light have acquired a peculiar 
property, which renders them incapable 
of being transmitted through the second, 
except when the two are held in a paral- 
lel position, and the rays are then said to 
be polarized. 

In some doubly refracting crystals the 
two oppositely polarized beams are of 



14 PRECIOUS STONES. 

different colors, so upon double refraction 
and polarization depends the property of 
many gems which is called pleiochroism. 

Pleiochroism. 
The dichroiscope is a handy little opti- 
cal instrument, that will readily serve to 
distinguish the diamond, spinel, or garnet 
(all singly refracting minerals) from the 
ruby, beryl, or any of the doubly re- 
fracting stones. This instrument consists 




of a cleavage rhombohedron of Iceland 
spar, fastened in a brass tube about 2-J- 
inches long, and { of an inch in diameter. 
A sliding cap at one end has a perfora- 
tion \ of an inch square, and at the other 
end is a lens which will show a distinct 



PLEIOCHROISM. 1 5 

image of the square opening when the 
cap is pulled out about \ of an inch. 

The pleiochroism of many stones can 
be determined at a glance with the 
dichroiscope. 

When a stone is examined by means of 
the dichroiscope, it will show two images 
of the same hue, or of different hues, 
these square images (fig. 1, A) forming a 
right angle and being more distinct when 
viewed from one part of the stone than 
from another. 

When the images are identical in color, 
the specimen may be a diamond, garnet, 
spinel, or glass. Should a red or ruby 
spinel approach the ruby in color, a quick 
and satisfactory test can be made with 
the dichroiscope, as the spinel will show 
two images of one color, while the ruby 
will show one image of aurora red and 
one of carmine red. 

The dichroiscope is inexpensive, cost- 
ing but a few dollars, and is very useful 
for rapidly deciding the species of many 



i6 



PRECIOUS STONES. 



stones. The following is a partial list of 
doubly refracting stones and their twin 
colors. 



NAME OF STONE. 


TWIN 


COLORS. 


Sapphire (blue) 


Greenish straw 


Blue 


Ruby (red) 


Aurora red 


Carmine red 


Tourmaline (red) 


Salmon 


Rose pink 


" (brownish red) 


Umber brown 


Columbine pink 


" (brown) 


Orange brown 


Greenish yellow 


" (green) 


Pistachio green 


Bluish green 


(blue) 


Greenish gray 


Indigo blue 


Emerald (green) 


Yellowish green 


Bluish green 


Topaz (sherry) 


Straw yellow 


Rose pink 


Peridot (pistachio) 


Brown yellow 


Sea green 


Aquamarine (sea green) 


Straw white 


Gray blue 


Beryl (pale blue) 


Sea green 


Azure blue 


Chrysoberyl (yellow) 


Golden brown 


Greenish yellow 


Iolite (lavender) 


Pale buff 


Indigo blue 


Amethyst (purple) 


Reddish purple 


Bluish purple 



Colors. 

The following is a partial list of the 

colors of precious stones : 

Shades of White. — Quartz, opal, chalce- 
dony. 

Shades of Gray. — Labrador, smoky to- 
paz, chalcedony, zircon. 

Black. — Obsidian, tourmaline, jet. 



LUSTRE. If 

Shades of Blue. — Lapis-lazuli, amethyst, 
chalcedony, spinel, zircon, sapphire, 
cyanite, tourmaline, turquois, odonto- 
lite, fluor spar. 

Shades of Green. — Amazon stone, tur- 
quois, prase, beryl, bloodstone, epidote, 
emerald, malachite, chrysoprase, chrys- 
olite, idocras, olivine, garnet, chryso- 
beryl. 

Shades of Yellow. — Opal, amber, topaz, 
beryl, jasper. 

Shades of Red. — Garnet, carnelian, chalce- 
dony, rose quartz, corundum, tourma- 
line, spinel, ruby. 

Shades of Brow7t. — Zircon, garnet, smoky 
topaz, axinite, jasper. 

Colorless. — Diamond, sapphire, spinel, zir- 
con, topaz, rock crystal, moonstone. 

Lustre. 

Well polished precious stones display a 
decided lustre, which assists in determin- 
ing their species. 



1 8 PRECIOUS STONES. 

The following is a list of some precious 
stones and their lustre : 
Adamantine. — Diamond, zircon. 
Resinous. — Garnet. 
Vitreous. — Emerald, ruby, spinel. 
Waxy. — Turquois. 
Pearly. — Moonstone, opal. 
Silky.— Crocidolite, quartz cat's-eye. 
Metallic. — H ematite. 
Greasy. — Olivine. 

Some stones vary in lustre, from vitreous 
to pearly, etc. 

Streak. 

The streak of a mineral is the color of 
its powder. 

This powder varies in color, and may be 
white, gray, red, etc. It is obtained by 
scratching the mineral with a sharp file, or 
by rubbing the mineral on the back of an 
unglazed porcelain plate, when the color 
of the powder will appear on the plate. 

It is remarkable that the streak of the 
diamond is gray to grayish-black, while 
that of the ruby is colorless or white. 



hardness. 1 9 

Hardness. 
One of the most important and distin- 
guishing qualities of a gem stone is the 
property of enduring, resisting wear, — in 
short, hardness. To test the hardness of 
precious stones that have not been cut or 
polished, the following scale of ten miner- 
als has been devised by Moh, a German 
mineralogist : 
No. 1. Talc. Very soft; is easily broken 

or scratched with the finger-nail. 
No. 2. Rock-salt. Soft ; scratched with 

difficulty with finger-nail ; readily cut 

with a knife. 
No. 3. Calcite. Low degree of hardness; 

not to be scratched with finger-nail ; 

easily scratched with a knife. 
No. 4. Fluor spar. Fairly hard ; is slightly 

scratched by a knife, but easily attacked 

with a file. 
No. 5. Apatite. Medium hardness ; does 

not scratch glass, or only faintly ; does 

not give out sparks against steel ; easi- 
ly attacked with a file. 



20 PRECIOUS STONES. 

No. 6. Felspar. Easily scratches glass ; 

is attacked by a file, and gives some 

sparks against steel. 
No. 7. Quartz. Quite hard; is only slight- 
ly attacked by file ; gives sparks readily 

against steel. 
No. 8. Topaz. Very hard ; is not attacked 

by a file. 
No. 9. Sapphire. Hardest of all minerals 

but the diamond ; attacks all other 

minerals. 
No. 10. Diamond. Attacks all minerals ; 

is not attacked by any. 
To find the hardness of a stone, begin 
to test with the softest mineral, so that 
when the number is reached which will 
scratch the stone, there has been no injury 
to the specimen under examination. Half 
numbers are determined by the ease or 
difficulty with which a stone is scratched. 
For example, a stone which will resist No. 
7 (quartz) and which is only faintly at- 
tacked by No. 8 (topaz) may be safely put 
down as 7.5, while a stone which resisted 



SPECIFIC GRAVITY. 21 

No. 7 and yielded easily to No. 8 is to be 
classed as 7 in hardness. 

These tests are readily applied to crys- 
tals or unpolished gems. With the pol- 
ished stone greater care must be observed, 
and while a file test is often satisfactory, 
there is always the danger of striking the 
cleavage and breaking off a small piece of 
the stone. 

Specific Gravity. 

One of the most important tests which 
can be applied to a polished stone is that 
of specific gravity. Many stones, like the 
ruby and the spinel, the blue tourmaline 
and the sapphire, etc., look alike, but there 
is a sensible difference in their respective 
weights that a specific-gravity test will 
readily establish. 

The weight of an object which is free to 
seek the centre of gravitation is called ab- 
solute weight, while the weight of an ob- 
ject compared with that of another con- 



22 PRECIOUS STONES. 

taining the same volume of matter is called 
the specific weight. 

If a stone weighing 16 carats is placed 
in a vessel filled to the brim with distilled 
water and the stone displaces 6 carats of 
water, the specific gravity of the stone 
would be 16 — 6, or 2.66, the specific 
gravity of quartz. 

In other words, the stone would weigh 
1 6 carats in the air and only io carats in 
the distilled water, showing a loss of 6 
carats, which is the weight of the volume of 
water equal in bulk to the stone ; — or ab- 
solute weight, 16 carats ; specific weight, 
io carats; loss, 6 carats; \6 -f- 6 = 2.66, 
specific gravity. 

There are several methods of ascertain- 
ing the specific gravity of a stone. 

First, by placing it in liquids of known 
specific gravity. 

Second, by weighing the stone in air 
and then in distilled water or alcohol, and 
thus learning the weight of an equal bulk 
of water. 



SPECIFIC GRAVITY. 23 

Third, by measuring or weighing the 
water which the stone displaces when 
immersed in a small vessel of known ca- 
pacity. 

Fourth, by means of the Nicholson 
hydrometer, a simple instrument consist- 
ing of a hollow glass cylinder, two dishes, 
and a glass vessel. 

As the jewelers' balances are well 
adapted for the ordinary work of taking 
specific gravity, or can be easily adapted 
for such work, the second method will 
usually be the more practical to follow. 

The author has had very satisfactory 
service from a $30 balance, and any well 
adjusted balance will give fair results. 

The following accessories are necessary 
to take the specific gravity of a stone : 

Distilled water about 6o° Fahr. 

A very fine thread of platinum wire 
with which to suspend the stone (fig 4 ). 

A glass-beaker for the water (fig. 3, C). 

A bench to hold the beaker over the 
pan (fig. 2). 




2 4 




PIG 3 



25 



26 PRECIOUS STONES. 

The distilled water is easily obtainable 
from any druggist. The platinum wire 
should be bent to hook into the top of 
the balance frame, (fig. 3, B) and for ordi- 
nary small stones it will be convenient 
to twist the other end into a cork-screw 
shape or receptacle (fig. 4, A). 

The beaker can be a small, thin glass 
cup of any kind, and the bench is easily 
produced from wood (fig. 2) or of metal 
with three supports (fig. 3, A). 

To ascertain the specific gravity, attach 
the platinum wire to the balance frame,(fig. 
3, B) and allow the lower end to rest in the 
water ; then balance this carefully by add- 
ing weights to the other side (fig. 3, D) 
until the balance is exact. 

The stone to be weighed in water is a 
ruby, and weighs two carats in the air. 

Clean the stone carefully with water to 
free it from air bubbles ; then place it in 
the screw of the wire (fig. 4, A) and weigh 
carefully. If the stone weighs \\ carats 
it will have displaced \ ct. of water : or, 



WEIGHT. 27 

weight in air, 2 carats ; weight in water, i£ 
carats ; loss, \ carat ; 2 -f- \ = 4, which 
will be the specific gravity of the ruby. 

The Jolly spiral balance can also be 
used for taking specific gravity, but it is 
not so practical or accurate for small 
stones as for the larger ones. 

Weight. 

The valuable precious stones are bought 
and sold by the carat. This weight is 
equal to about 3.17 grains or about .205 
milligrams. 

The carat is divided into fractions of |-, 
h h tV> A"> 6T> an< 3 also arbitrarily into 
four grains ; that is, each quarter of a carat 
is counted one grain, thus forming the 
basis for the calculation of pearls. 

In commerce, a carat diamond is some- 
times called a four-grain stone, and a carat- 
and-a-half stone is six grains, etc., etc. 

The weight of the carat being arbitrary, 
it varies in different countries, some being 
heavier and others lighter than .205 milli- 
grams. 



28 PRECIOUS STONES. 

The writer wrote to three prominent 
balance-makers in the United States some 
months ago for their carat standards and 
was surprised to find that they all differed. 
This will account for discrepancies in 
weight resulting between the balances of 
different makers. Of late there has been 
a decided movement in Europe, headed 
by the French Chambre Syndicale of jew- 
elers, in favor of the unification of the 
carat, so that the weight of a French or 
Dutch carat will equal that of an English, 
American, or any other carat. This re- 
form will probably be accompanied by 
the adoption of the decimal system of 
dividing the carat, and the discarding of 
the complicated fractional system. 

After having tried the decimal weights 
for many months, the author can testify 
to a decided gain in time and accuracy 
from their use. 

Fusibility. 
The blow-pipe or dry test for minerals 



FUSIBILITY. 29 

is convenient to apply to small bits or 
splinters of a stone. 

The mineral is either held by a pair of 
platina-pointed forceps, or powdered and 
placed on a metal plate or in a glass tube. 

Before the blow-pipe, some minerals 
change color, but do not melt, while 
others retain their color, or swell up, or 
break into small particles, or melt into 
colorless or colored glasses. 

The following is the scale of minerals 
used to test the different degrees of fusi- 
bility : 

1. Gray Antimony. Fusible in coarse 

splinters in summit of candle flame 
without the blow-pipe. 

2. Natrolite. Fusible in fine splinters in 
the summit of a candle flame without 
the blow-pipe. 

3. Almandite. Does not fuse in candle 

flame ; fuses easily before the blow- 
pipe in obtuse pieces. 

4. Green Actinolite. Fusible before the 
blow-pipe in coarse splinters. 



30 PRECIOUS STONES. 

5. Orthoclase. Fusible before the blow- 
pipe in fine splinters. 

6. Bronzite. Before the blow-pipe be- 
comes rounded only on the sharp 
edges. 

Magnetism. 

There are but few precious stones that 
possess the power to act on the magnetic 
needle ; among them are the chrysolite, 
cinnamon stone, almandine, pyrope, and 
garnet. 

Transparency. 

Precious stones are, on the basis of their 
relative transparency, divided into four 
classes, as follows : Transparent, or ad- 
mitting light freely and clearly; defining 
objects when used as a lens. Semi-trans- 
parent, admitting light, but only partially 
defining objects. Translucent, admitting 
light faintly. Opaque, not admitting light. 

The more valuable precious stones, ex- 
cepting opals and turquoises, are generally 
transparent. 



phosphorescence. — electricity. 3 1 
Phosphorescence. 

Some precious stones display a distinct 
phosphorescence after exposure to the 
sunlight, and also upon the application of 
artificial heat, and through mechanical and 
electrical means. 

Many diamonds, when taken to a dark 
room, appear quite luminous ; this is also 
true of topaz, fluor spar, and other miner- 
als. 

Electricity. 

Minerals acquire electricity through 
friction or heating, and in this state read- 
ily attract or repel small bits of paper and 
other light substances. 

All minerals are electric, some display- 
ing positive and others negative electricity. 

The electric test of a precious stone re- 
fers to the length of time that a stone will 
retain electricity after friction or heating. 

Some stones lose this quality in a few 
minutes, while others retain it a long time. 



32 PRECIOUS STONES. 

The tourmaline is noted for its electrical 
properties, while the Brazilian topaz ren- 
dered electric by heating or rubbing has 
been known to affect the electric needle 
after 32 hours. 

Cutting and Polishing. 

Although a finely developed diamond, 
ruby, or other crystal is sometimes found 
and used for jewelry, the beauty of a 
precious stone generally remains hidden 
within a rough and unsightly exterior 
until the lapidary's art reveals the gem. 

According to well known rules, there is 
one kind of cutting or faceting for the 
diamond or colorless gems and another for 
colored gems. 

The brilliant cut, figs. 5 and 6, consists of 
an arrangement of fifty-six facets, exclusive 
of the table and culet. This cut is some- 
times improved by the addition of eight 
star facets around the culet, which brings 
the number of facets up to sixty-four. 



CUTTING AND POLISHING. 



33 



The following are the proportions of a 
well cut diamond or colorless gem : 
\ above the girdle, fig. 6, A. 
| below " " " 6, B. 
The table f of the breadth of the stone, 

fig.6,C. 
The culet ^ of the size of the table, fig. 

6, D. 




IIQ.5 




These proportions do not refer to colored 
gems, which are cut thick or shallow to 
deepen or diminish the color of the stone. 
The step cut, fig. 7, now principally used 
for emeralds, can be advantageously used 
for other colored stones. 

The crowned rose cut, fig. 8, is applied 
to small diamonds, and occasionally to col- 



34 



PRECIOUS STONES. 



ored gems. This cut consists of twenty- 
four facets, and a well proportioned rose 
is one half of its diameter in thickness. 




rrG.7 





Eis.a 



TIG.VQ 



To the smaller and more common roses 
only twelve facets are given. 

Besides the above-mentioned forms, 
there are the : 

Huitpan, or single cut. 

16 facet " double " 

24 " " single brilliant. 

Cabochon " carbuncle. 

Star cut, fig. 9. 

Degree or rose cut, fig. 10. 



DIAMOND. 35 

The last two beautiful forms of cutting 
are frequently given to fine paste or imita- 
tion diamonds. 

Of late years nearly all gems have been 
cut quite round, and in many instances 
with a sacrifice of size and brilliancy. 

Diamond. 

The diamond is one of the most precious 
minerals, and yet it consists of pure 
carbon, the most common substance that 
is known, a substance that is present in all 
animal and vegetable bodies and in the 
larger number of minerals. When carbon 
is crystallized the result is the diamond, 
which is always found in detached crystals, 
either octahedrons or rhombic dodecahe- 
drons, the planes of the angles being often 
convex or rounded, — this curving crystal 
being peculiar to the diamond. 

The cleavage is perfect, and, parallel to 
the faces of the octahedron, the fracture is 
conchoidal or curved. The diamond is 
not acted upon by acids or alkalies, is in- 



36 PRECIOUS STONES. 

fusible but combustible, and burns under 
heat of a very high temperature. Dia- 
mond powder burns readily, but larger 
pieces are not affected by the blow-pipe. 

The diamond is a non-conductor of 
electricity, but acquires positive electricity 
when rubbed, and retains it for half an 
hour. After being exposed to the solar 
rays, the diamond presents a distinct 
phosphorescence in the dark. It possesses 
single refraction, but belongs to those 
bodies which reflect light most strongly, 
and its magnifying power is much greater 
than that of glass ; it does not polarize 
light ; its lustre is adamantine, and specific 
gravity 3.5 to 3.6. The diamond is the 
hardest of all known minerals, ranking 
No. 10 in Moh's scale of hardness. 

White, and the different shades from 
very light yellow to dark yellow or ca- 
nary, comprise, according to the popular 
idea, the colors of the diamond. Yet the 
diamond is found in green, red, blue, 
brown, olive, orange, and black, and also 



DIAMOND 37 

in the various shadings of these colors 
and in opalescent tints. 

As the limpid or white diamond sur- 
passes all other white stones in the power 
of its lustre and the magnificence of its 
fire, so do the colored diamonds outrank 
the emerald, ruby, sapphire, and other 
gems of like colors. 

Colored diamonds, excepting light yel- 
low and brown, are rare, and hence are 
the most valuable of precious stones. 
The limpid or perfectly white and the 
white with a bluish tint are the most 
sought after, while fine deep golden yel- 
low or canaries and pronounced fancy 
colors always find a ready market. 

Diamonds come principally from the 
mines in South Africa ; some are found 
in Brazil and India, and fewer in Sumatra, 
Borneo, the Ural Mountains, and Aus- 
tralia. Crystals have also been found in 
the United States. 

The amorphous or carbon diamond is 
found only in Brazil. The pebbles or 



38 PRECIOUS STONES. 

masses are opaque, steel-gray to black in 
color, and sometimes weigh 1,000 carats. 

This carbonate is principally used to 
point rock-drills and for other engineering 
purposes. The coarse variety of crys- 
tallized diamonds is called bort, and as 
this is unfitted for gem purposes because 
of imperfections, it is ground into powder 
and used for cutting and drilling precious 
stones. 

White sapphires, white zircons, white 
topaz, and rock-crystal sometimes pass 
for diamonds. The first two are heavier, 
the topaz lacks brilliancy, and the crystal 
is lighter than the diamond. 

It is also the case that these four stones, 
especially the crystal, are easily scratched 
by a diamond. 

The best style of cutting for a diamond 
is the brilliant, of 66 facets, including the 
table and culet. The proper proportions 
of a well cut brilliant is -J- for the crown 
and f for the collet. The table and culet 
must also be in proportion to the size of 
the stone. 



corundum. 39 

Corundum. 

This many-colored mineral, composed 
of nearly pure alumina, produces gems 
which in some cases are more valuable 
even than diamonds. The ruby, sapphire, 
Oriental emerald, Oriental topaz, Oriental 
amethyst, Oriental aquamarine, Oriental 
chrysolite, Oriental hyacinth, star ruby, 
star sapphire, star topaz, and ruby and 
sapphire cat's-eyes are all corundums of 
different colors. The ruby is a red sap- 
phire, and the Oriental topaz a yellow 
sapphire, while the Oriental emerald is a 
green sapphire, etc., etc. 

In hardness corundum ranks next to 
the diamond, ranking No. 9 in Moh's scale. 

The specific gravity is 3.9 to 4.1, the 
crystallization rhombohedral, and cleavage 
basal, the crystals breaking across the 
prism with nearly a flat surface. 

In lustre, the corundum is vitreous, its 
refraction double but not to a high de- 
gree, and it is susceptible of electricity 
by friction, which the polished specimens 
especially retain for a considerable time. 



40 PRECIOUS STONES. 

Corundum is unaffected by chemicals, 
and is infusible alone, but in combination 
with a flux it melts with difficulty into a 
clear glass. 

The chemical composition of precious 
corundum is : 

Alumina, 98.5 

Oxide of iron, 1.0 
Lime, o. 5 



100. 

Thus it will be seen that corundum is 
composed almost wholly of alumina, — 
one of the constituents of common clay, 
which, when colored by traces of metallic 
oxides, chrome, etc., produces a greater 
variety of precious stones of a high rank 
than any other mineral. 

The Ruby. 
The red sapphire or ruby is the most 
valuable of the corundum family, and 
when found of a good color, pure and 
brilliant, and in sizes of one carat and 
larger, it is much more valuable than a 
fine diamond of the same size. 



THE RUBY. 41 

Fine rubies larger than \\ to 2 carats 
are very rare, and when a fine stone from 
3 to 5 carats is offered for sale, the price 
mounts into the thousands. 

The color varies from the lightest rose 
tint to the deepest carmine ; that color, 
however, which has the greatest value is 
known in commerce as pigeon's blood, and 
is the color of arterial blood, or of the very- 
centre of the red ray in the solar spectrum. 

The imperfections in rubies, as in all 
corundums, consist largely of clouds, 
milky spots, and cracks. A perfect ruby 
is rarely met with, and a stone possessing 
brilliancy and the true color, even if 
slightly defective, is considered more 
valuable than an absolutely perfect ruby 
of an inferior color. 

Rubies are found in Siam, Ceylon, Bur- 
mah, Brazil, Hindustan, Borneo, Sumatra, 
Australia, France, and Germany. 

Where rubies and sapphires are met 
with it is said that gold is almost sure to 
be present. 



42 PRECIOUS STONES. 

Chemists have succeeded in producing 
minute crystals of rubies and sapphires 
which, under the microscope, presented 
the true crystallization of corundums, and 
upon being tested proved to be of the 
same hardness as rubies and sapphires; 
but these specimens were small, and cost 
very much more to produce than their 
commercial value. 

Ruby spinels, garnets, hyacinths, red 
quartz, burnt Brazilian or rose topaz, and 
red tourmaline are sometimes passed off 
for the ruby. 

The true ruby will scratch all of these 
stones readily, the spinel is lighter in 
specific gravity, and has generally a slight 
tinge of yellow, even in the most pro- 
nounced red specimens. 

The ruby will turn green under the 
flames of a blow-pipe, but when cooled 
off, resumes its original color. 

The garnet and topaz are easily scratched 
by the ruby, the hyacinth is heavier, and 
quartz and tourmaline lighter than the 



SAPPHIRE. 43 

ruby. Some so-called reconstructed ru- 
bies, recently offered for sale, are of a 
very fine color, and closely resemble the 
Oriental gems. 

The hardness and specific gravity are 
the same, but they differ in one very im- 
portant point, namely: they lack the 
brilliancy of the true ruby. In addition 
to this lack of fire, a microscopical test 
discloses formations which will distinguish 
the manufactured from the natural stone. 

Sapphire. 

The blue corundum, ranging in color 
from the lightest blue to deep blue and 
black, is the same stone as the ruby, the 
only difference being in the color. 

The choicest color is the soft velvety 
blue, approaching the corn-flower in shade 
and exhibiting that color vividly by arti- 
ficial as well as by natural light. 

The deeper-colored stones are known as 
male, and the light-colored ones as female 
sapphires. 



44 PRECIOUS STONES. 

Although choice sapphires are rare, a 
much greater quantity of good and large 
stones are to be had than of rubies, and 
therefore the price of a large sapphire does 
not advance in the same proportion as the 
price of a large ruby. 

Fancy Sapphires. 

The Oriental emerald or green sapphire 
does not approach the beryl or true 
emerald in depth of color, but because of 
its superior hardness and brilliancy, added 
to its extreme rarity, it is the most valua- 
ble of green gems. The Oriental amethyst 
or purple sapphire sometimes reflects a 
red color by artificial light, and is valued 
highly as a gem stone ; the common 
amethyst is softer, less brilliant, and loses 
by artificial light. 

The various other colored sapphires, 
such as yellow or Oriental topaz, light 
green or Oriental aquamarine, greenish- 
yellow or Oriental chrysolite, and aurora- 
red or Oriental hyacinth, are all valuable 



STAR SAPPHIRES. 45 

as gem stones when they are pure, well 
cut, and have pronounced colors — in fact, 
the name Oriental is given to distinguish 
the corundums from the less valuable 
minerals of the same colors which they 
resemble, but which they greatly surpass 
in beauty and value because of their bril- 
liancy and superior hardness. 

Star Sapphires. 

Asterias or star stones are corundums 
of three different colors ; the star sapphire 
proper is a grayish blue, the star ruby red, 
and the star topaz yellow. 

These stones are usually cut cabochon 
or convex, and display under the rays of 
the sun, or when exposed to one candle or 
other artificial light, a beautiful star with 
six points. 

This star is produced by foreign sub- 
stances in the corundum, and the lapidary 
brings about the regular effect by cutting 
a pointed carbuncle so that the centre of 
the star begins at the apex, and the six 



4-6 PRECIOUS STONES. 

bright stripes radiate to the base of the 
stone. 

The bright lines of the star following 
the light move over the surface of the 
stone and produce a remarkable effect. 
These stones are amongst the most won- 
derful of mineral productions, and good 
specimens are very valuable. 

The corundum cat's-eye, called Oriental 
girasol or sunstone, has a bluish, reddish, 
or yellowish reflection of light of a lighter 
shade than the stone itself, and which 
moves on the convex surface of the stone 
like the lines of a star stone. 

Spinel. 

It is only during the past century that 
mineralogists make a distinction between 
the minerals spinel and corundum. 

The composition of the spinel was dis- 
covered towards the end of the last cen- 
tury, and was found to be about seventy 
per cent, alumina, twenty-five per cent, 
magnesia, and small parts of oxide of 
chrome, silica, and protoxide of iron. 



SPINEL. 47 

Up to that time, red spinels had always 
been confounded with rubies, and many 
celebrated so-called rubies have been 
shown to be spinels by modern mineralo- 
gists. 

This beautiful mineral is found in many 
colors, from pink to rose-red, carmine, 
cochineal, blood-red, hyacinth, pale to 
dark blue, violet and indigo blue, grass- 
green to blackish green, and sometimes 
colorless. There is also a black variety 
called pleonaste or ceylonite. Spinels crys- 
tallize in octahedrons and their modifica- 
tions, the fracture is conchoidal, specific 
gravity 3.5 to 3.6, and hardness No. 8 in 
Moh's scale ; only the diamond, corundum 
and chrysoberyl will scratch the spinel. 

Its refraction is single, the lustre highly 
vitreous, and it does not easily acquire 
electricity. 

Acids do not attack the spinel, nor has 
the blow-pipe any effect on this mineral, 
except to change the red to a brownish 
or colorless state, but the original color 
returns when the stone cools. 



48 PRECIOUS STONES. 

Flawed or imperfect stones are liable to 
crack or split if heated too much. With 
borax or salt of phosphorus the spinel 
melts into a colorless or green-tinted 
glass. 

Spinels are found in clay and in the 
sands of rivers, in East India, Hindustan, 
the province of Mysore, Farther India, 
Pegu, Ceylon, North America, Sweden, 
Bohemia, and Australia. 

The red spinel, and especially those tints 
which approach the red corundum or true 
ruby in color, are the most valuable, and 
are known as ruby spinels. 

Very fine specimens of ruby spinels of 
one carat and larger are quite rare and 
command good prices. 

Rose-colored spinels are known as balas- 
rubies, pale-blue spinels as sapphirines, 
and the hyacinth-red, yellowish-red, and 
orange-yellow spinels are called rubicelles. 

All these different-colored spinels, if 
pure and of great brilliancy, are valuable 
as gem stones, being only surpassed in 



SPINEL. 49 

hardness and brilliancy by the diamond 
and corundums. 

The white spinel, which is seldom found, 
is sometimes confounded with the dia- 
mond, having the same specific gravity 
and single refraction, but as it lacks the 
fire and is easily scratched by the diamond, 
the danger of mistaking one for the other 
is slight. Burnt amethyst, which often 
resembles the spinel, is lighter and softer, 
while burnt topaz, although it is identical 
with the spinel in hardness, is somewhat 
lighter and possesses remarkable electric 
powers, becoming electric by either rub- 
bing, heating, or pressure, and retaining 
electricity for upwards of twenty-four 
hours. 

The zircon is easily distinguished from 
the spinel because of its much greater 
specific gravity. It is also doubly refrac- 
tive and softer. 

Garnets are softer, lack the play of color 
and brilliancy, and fuse easily into a light- 
brown or black glass. 



SO PRECIOUS STONES. 

Beryl. 

The beryl is a mineral belonging to the 
primitive formation, and is found in quartz 
veins and granite. 

It crystallizes in six-sided prisms and is 
composed largely of silica, the third most 
common of earth's productions. The 
beryl is 7.5 to 8. in hardness, scratching 
quartz, but is scratched by topaz. 

The specific gravity is 2.67 to 2.73, 
making it one of the light minerals. 
Its lustre is vitreous and refraction double 
to a slight degree ; its cleavage is imper- 
fectly basal, and it becomes electric by 
rubbing. 

Acids do not attack the beryl, but it 
melts with borax and is soluble in salts of 
phosphorus. 

This stone is found in various colors, 
grass-green, pale-green, light-blue, green- 
ish-blue, greenish-yellow, yellow, and some- 
times pink. 

The most important of these colors is 
the grass-green, which forms a separate 



EMERALD. 5 1 

division of the beryl family, and is known 
as the emerald. 

Emerald. 

The emerald or green beryl is one of 
the most highly prized of the gem stones. 
Its magnificent color has rightly been 
compared to the color of the fresh grass 
in spring, and in brilliancy this stone far 
exceeds all other green gems, excepting 
only the very rare green corundrum or 
green sapphire. 

The emerald is said to be very soft 
when first withdrawn from the mine, but 
it hardens by exposure to the air. 

A perfect emerald of fair size is a rarity, 
so that the saying " an emerald without 
a flaw " has passed into a proverb. 

This stone is so light, compared to a 
diamond or sapphire, that a carat emerald 
will be very much larger than either of 
the above stones. 

The emerald is composed of : 



52 PRECIOUS STONES. 

Silica 68.50 

Alumina . . . .15.75 

Glucina 12.50 

Peroxide of iron . . 1. 

Lime 0.25 

Oxide of chrome . . 0.30 
And traces of magnesia, of lime, and of soda. 

The vivid green color of the emerald is 
supposed to come from the oxide of 
chrome, as the other beryls do not con- 
tain chrome. 

Emeralds are found in New Granada, 
near Bogota, Egypt, East India, Burmah, 
Ural in Europe ; Salzburg, Austria ; Mt. 
Remarkable, South Australia ; and North 
America. Some of the finest come from 
the mines of Muza, near Bogota, and the 
best stones are called Peruvian emeralds. 
During the conquest of Peru by the Span- 
iards, many very fine emeralds were de- 
stroyed by the invaders, who tested them 
by grinding and pounding, and concluded 
that the emeralds were worthless, because 
they were not as hard as the diamonds or 
sapphires. 



BERYL. 53 

In 1587, Joseph D'Acosta returned to 
Spain with two cases of emeralds, each 
case weighing one hundred pounds. 

Green tourmaline sometimes passes for 
the emerald, but it is somewhat softer 
and considerably heavier. 

Olivines or chrysolites, if of a fine green 
color, sometimes resemble the emerald, 
but they are much heavier than the em- 
erald and have a fatty lustre. Green spi- 
nels are heavier and harder than emeralds. 

Beryl. 

The second and less valuable division 
of the beryl family comprises the follow- 
ing colors : 

Clear light sky-blue, called by lapidaries 
aquamarine ; very light greenish-blue, 
known as Siberian aquamarine ; and a 
greenish-yellow variety, called aquama- 
rine chrysolite. 

These three kinds are usually very bril- 
liant, and especially so by artificial light, 
in which respect the beryl is superior to 



54 PRECIOUS STONES. 

many of the more valuable gem stones. 
Beryls of very large size have been found 
in New Hampshire, one of which has been 
estimated to weigh over two tons. While 
the large specimens are worthless for gem 
stones, some very handsome aquamarines 
and golden-yellow beryls have been found 
during the past few years in New Hamp- 
shire and Connecticut. These stones, 
when cut, compare favorably with the 
best of their kind. 

Chrysoberyl. 

The name chrysoberyl is derived from 
two Greek words signifying golden-beryl. 
This name is well suited to the golden- 
yellow variety, but the chrysoberyl also 
includes many other colors : such as green, 
greenish-yellow, brownish-yellow, white, 
and dark-brown to black. 

Three varieties of chrysoberyls are 
known as cat's-eyes, cymophanes, and 
alexandrites. 

The chrysoberyl crystallizes in the 



CIIR Y SOBER YL. 5 5 

trimetric or rhombic system ; the cleav- 
age is imperfect ; fracture conchoidal ; 
hardness, 8.5, being the third hardest 
stone ; specific gravity, 3.65 to 3.8 ; and 
lustre vitreous to greasy. 

The composition of the chrysoberyl is: 
alumina, 80.2 ; glucina, 19.8 ; with traces 
of protoxide of iron and oxides of lead 
and copper. The chrysoberyl is doubly 
refractive to a high degree, acquires posi- 
tive electricity lasting several hours, is 
infusible alone, but melts with borax or 
salts of phosphorus to a clear glass, 
though with difficulty. 

The chrysoberyl is unaffected by acids, 
but with a solution of cobalt nitrate the 
powdered mineral becomes blue. 

Transparent greenish-yellow chryso- 
beryls are sometimes called Oriental 
chrysolites. These, and the brownish- 
yellow stones are the gems most used in 
jewelry. 

The chrysoberyl cat's-eye, or Ceylon 
cat's-eye, is found in various shadings of 



$6 PRECIOUS STONES. 

yellow, brown, and green, and sometimes 
nearly black. These stones are translu- 
cent to opaque, and have a bright band 
of light running through the centre. 
This band is nearly always white, and in 
fine specimens is sharply defined, not too 
wide, and is in the centre of the stone. 

The cat's-eye chrysoberyls are always 
cut convex or cabochon shape, and as the 
stone is moved from side to side the band 
of light moves over its surface. 

Cymophane. 

The cymophane, or floating light, as 
the name denotes, is a chrysoberyl with a 
bright spot of light which seems to float 
over the surface as the stone is moved. 
The cymophane is also cut cabochon. 

Alexandrite. 

On the day that the Emperor Alexan- 
der of Russia attained his majority the 
Ural chrysoberyl, of a dark-green color, 



ALEXANDRITE. 57 

was found in the emerald mines of Tako- 
waja in the Catherine Mountains. 

This wonderful stone is emerald-green 
to dark-green in color, with often a slight 
red tint, but by artificial light the green 
of good specimens changes to a beautiful 
columbine-red. 

As the colors green and red are the 
national colors of Russia, and the date of 
discovery of this stone in Russia occurred 
on the Emperor's birthday, the name 
alexandrite was given to this species of 
chrysoberyl. 

The alexandrite is found in large pieces, 
but is nearly always flawed and cracked. 
This is a much-sought-after gem stone, 
and specimens of from one to five carats 
command good prices. Up to the present 
time, however, good alexandrites have 
been rare, and the demand has always ex- 
ceeded the supply. 

Cat's-eyes and cymophanes are found in 
Brazil in alluvial deposits of rivers, and 
consequently in rolled and rubbed masses. 



58 PRECIOUS STONES. 

Chrysoberyls are also found in Russia, 
Germany, America, Borneo, Pegu, and 
Moravia. 

Chrysolites and topazes are sometimes 
passed off for chrysoberyls. The chryso- 
lite is, however, lighter and softer, while 
the topaz becomes electric from heating, 
and is softer. 

Quartz cat's-eyes, which are mistaken 
for chrysoberyl or Oriental cat's-eyes, have 
a specific gravity of about 2.65, hardness 
of 6 to 6.5, and are soluble in fluoric acid, 
besides melting with soda into a clear 
glass. 

They lack the bright, hard polish of the 
chrysoberyl cat's-eye, and there should be 
no difficulty in discovering the difference 
between the gem and the inferior stone. 

Zircon. 

The zircon, hyacinth, jacinth, or jargoon 
belong to the tetragonal system of crys- 
tallization. The cleavage is imperfect, 



zircon. 59 

fracture conchoidal, and specific gravity 
4.4 to 4.7, the stone being much heavier 
than any other gems. Its hardness is 7.5 
and lustre vitreous to adamantine, and 
refraction double to a high degree. 

The zircon is phosphorescent when 
heated ; before the blow-pipe it is infusible, 
but loses its color; and with borax it melts 
into a transparent glass. Sulphuric acid 
affects this gem after long maceration. 

The composition of the zircon is : zir- 
conia, 66.3 ; silica, 33.7 ; with a trace of 
peroxide of iron. 

Under the microscope, the texture of 
these gems presents a watery appearance, 
called by the French rating and which 
looks like a liqueur poured into water. 
This is a strong distinguishing point in the 
zircon. 

The zircon, hyacinth, jargoon, and ja- 
cinth are the same gems but of different 
colors. 

The brown, violet, and green colors are 
known as zircons, the red as hyacinth, the 



6o PRECIOUS STONES. 

yellow as jacinth, and the grayish- white 
and white as jargoons. 

The jargoon has often been palmed off 
as a diamond because of its transparent 
color and adamantine lustre. 

The zircon is found in Ceylon, Germa- 
ny, France, Bohemia, America, and in fact 
in nearly all parts of the earth, as many as 
120 localities having been noted where 
specimens of the mineral have been dis- 
covered. 

The zircon can be distinguished from 
the garnet by its peculiar diamond-like 
brilliancy and its specific gravity. 

TURQUOIS. 

The turquois is never found in crystals, 
but in reniform or stalactitic masses. The 
color varies from pea- and apple-green to 
greenish-blue, sky-blue and dark-blue. 

The hardness of the turquois is 6., 
specific gravity 2.6 to 2.8, lustre waxy, and 
condition opaque to slightly translucent. 



TURQUOIS. 6 1 

Before the reducing flame of the blow- 
pipe, the turquois does not melt, but be- 
comes brown and colors the flame green. 
With borax and salts of phosphorus the 
turquois melts to a clear glass, while it is 
also soluble in hydrochloric acid. Orien- 
tal or mineral turquois is composed of : 



Alumina 
Phosphoric acid 
Water . . . 
Oxide of copper 
Iron .... 
Oxide of manganese 
Phosphate of lime 



47-45 
27.34 
18.18 
2.02 
1. 10 
0.50 
3.41 

100.00 



The best color is a clear deep sky-blue, 
and in the true turquois this color improves 
by artificial light ; imitation turquoises, 
however, lose their fine color under the 
same conditions. 

The finest gem turquoises come from 
the northeastern part of Persia, between 
Nishapoor and Meshed. Here they are 
mined and partly cut, and then the Persian 
merchants carry them to Russia, where 



62 PRECIOUS STONES. 

they are sold at the great annual fair of 
Nijni-Novgorod and in Moscow. Mineral 
turquoises are also found in New Mexico, 
Arizona, and Nevada, but not of sufficient 
size or sufficiently good color to make 
gem stones, although they are prized for 
collections. Specimens are also found in 
Burmah, Khorassan, Thibet, China, Sile- 
sia, Saxony, and on the Isthmus of Suez. 
The stones from these places have, as a 
rule, but little value, as the color fades or 
turns green from exposure to the light. Of 
late however, some very good turquoises 
have come from Egypt. The color of a 
faded Persian turquois can sometimes be 
restored by simply repolishing the stone. 

Occidental or bone turquoises called 
new rock or odontolites, to distinguish 
them from the Persian or old rock stones, 
are of organic origin. 

They are cut from the teeth of mam- 
moths, mastodons, dinotheriums, etc., and 
are found near the town of Simor, in 
Lower Languedoc, France. 



TURQUOIS, 63 

These teeth, the enamel of which is 
nearly as hard as the mineral turquois, 
are colored by contact with phosphate of 
iron and copper, which gives them a dark- 
blue, light-blue, and bluish-green color. 
They are easily attacked by a file, and 
totally destroyed by aqua-fortis. 

When heated, the fossil turquois or 
odontolite gives an offensive odor, owing 
to the decomposition of animal matter. 

The odontolite is lighter than the min- 
eral turquois, changes color by artificial 
light, loses color in distilled water and 
alcohol, and is translucent on the edges. 

This fossil turquois does not fade like 
the mineral turquois, but by artificial light 
appears of a dirty grayish-blue. 

Turquoises are sometimes artificially 
stained, but this can be detected by 
applying a drop of ammonia to the back 
of the stone, and if the color is artificial 
the ammonia will eat it off, leaving a 
green spot. Ammonia does not affect the 
color of the Persian turquois. The so- 



64 PRECIOUS STONES. 

called " reconstructed " turquoises are very 
close imitations of the real, but are easily 
distinguished, as they change rapidly to a 
deeper blue when immersed in water, and 
while wet the surface of the stone shows 
cracks in every direction. These stones 
become softer through soaking in water or 
alcohol. The original color, however, 
returns when the stone is dry, but the 
cracks remain in faint outline. 

Tourmaline. 

The tourmaline or precious schorl is 
known under many different names, and 
no other mineral has such a suite of colors. 

The colorless variety is known as 
achroite ; the red, as rubellite or siberite ; 
the blue, indicolite or Brazilian sapphire ; 
the green, Brazilian emerald ; and the 
yellowish-green, Ceylon chrysolite or 
Ceylon peridot. Besides the above colors 
and their shadings, the tourmaline occurs 
in black and brown. 



TO URMA LINE. 6$ 

The crystallization is obtuse rhomboid, 
and generally forms six-, nine-, and twelve- 
sided prisms. 

Some of the crystals are very large, 
specimens over eight inches long having 
been mined. 

The tourmaline crystals are remarkable 
for their varied and beautiful groupings of 
colors. Some are internally blue or brown, 
surrounded by a bright carmine red or 
dull yellow ; others are red internally and 
are enveloped by a green exterior ; crystals 
are sometimes pink at the summit and 
light green at the base, or crimson tipped 
with black, or white at one end shading 
into green and finally into red at the other 
end. The hardness of the tourmaline is 
7 to 7.5, specific gravity 3 to 3.1, and 
lustre vitreous. 

The tourmaline becomes decidedly 
electric by heating or rubbing, and will 
readily attract small pieces of paper and 
other small objects. The rubellite or red 
tourmaline is composed of: 



66 PRECIOUS STONES. 

Silica 42.13 

Alumina 36.43 

Boracic acid 5.74 

Oxide of manganese . . 6.32 

Lime 1.20 

Potash 2.41 

Lithia 2.04 

The green tourmaline is composed of 

Silica 40. 

Alumina 39. 16 

Lithia and potash . . . 3.59 
Protoxide of iron . . . 5.96 
Protoxide of manganese . 2.14 

Boracic acid 4.59 

Volatile matter . . . . 1.58 



The tourmaline possesses double refrac- 
tion to a high degree, and its power of 
polarizing light is so great that, cut into 
slices, it is used in the polariscope for 
analyzing other minerals. 

If two slices of tourmaline, cut parallel 
to their axis, be laid one on the other in 
one direction, both are transparent ; if 
laid in another direction they become 
opaque, and if a doubly refracting crystal 
be placed between the two plates of 



TOURMALINE. 6? 

tourmaline, the part covered by the crystal 
is transparent while the other is opaque. 

Tourmaline melts with borax into a 
transparent glass ; the rubellite turns 
white, and the indicolite and green tour- 
malines turn black, under the blow-pipe. 

Tourmalines can be distinguished from 
othergems by theirspecific gravity,but prin- 
cipally by their property of assuming po- 
laric electricity after being heated, one end 
becoming positive and the other negative. 

The history of the discovery of the 
tourmaline and its electric property is a 
curious one. 

On a warm summer day, early in the 
eighteenth century, some children were 
playing in a courtyard in Amsterdam. 
Amongst their playthings were some pre- 
cious stones which the Dutch navigators 
had brought from Ceylon. Some of the 
stones seemed to be possessed of the 
strange power of attracting and repelling 
small bits of straw, ashes, and other light 
substances. The little ones called their 



68 PRECIOUS STONES. 

parents to witness this strange phenom- 
enon, and the stolid Dutch lapidaries, 
themselves puzzled at the sight, called the 
stones aschentreckers or ash-drawers. 

A number of years afterwards, careful 
experiments disclosed the wonderful elec- 
tric powers of the aschentreckers or tour- 
malines. Purple, green, and blue tour- 
malines are found in Brazil. In Ceylon 
the stones are found in gravel beds. Ru- 
bellites or siberites are found in Siberia. 

Tourmalines are also found in Moravia, 
the island of Elba, Sweden, Burmah, 
Tyrol, Canada, and the United States. 

The first tourmaline deposits known in 
the United States were discovered at Paris, 
Maine, in 1820. Another wonderful de- 
posit was found at Mt. Apatite in Maine 
in 1882, and up to the present time the 
finest tourmaline crystals have been dis- 
covered in the United States. 

Really fine specimens of red, blue, or 
green tourmalines are uncommon and com- 
mand very good prices. 



OPAL. 69 

Opal. 

The precious or noble opal, fire opal, 
common opal, hydrophane, and cachelong 
are different varieties of a mineral that is 
composed of about nine parts silica and 
one part water. 

The colors vary from chalky-white to 
bluish-white, from yellow to red, and" from 
a slight play of colors to the beautiful 
mingling of green, blue, and red with the 
most remarkable kaleidoscopic effects. 

The opal is 5.5 to 6 in hardness, specific 
gravity 2 to 2.1, lustre glassy, and trans- 
lucent from a slight to a very high degree. 

The opal is found in an amorphous 
state and never crystallizes ; in fact from 
the condition of the pockets in which this 
mineral is found, the indications are that 
the substance was once a fluid. 

Under the blow-pipe the opal loses its 
translucency and cracks but does not melt. 
Sulphuric acid will cause it to turn black, 
and in a cold solution of caustic potash 
the opal is almost entirely soluble. 



JO PRECIOUS STONES. 

The precious or noble opal is found 
chiefly in the mines of Czernowitza, be- 
tween Kaschau and Eperies, in Hungary, 
and in Gracias a Dios, a province in 
Honduras. 

In olden times, the Greek and Turkish 
merchants carried opals from Hungary to 
the Orient, and then they were shipped to 
Holland and sold in Europe as Oriental 
opals. 

The fire opal is of a yellowish-red color, 
and is found chiefly in Mexico, although 
it also occurs in Hungary, the Faroe 
Islands, Honduras, and Guatemala. 

The common opal is found in Ireland, 
Denmark, Frankfurt, Guatemala, and 
South Australia, and also in Hungary 
and Mexico. These opals are translucent 
without fire or reflection. 

The hydrophane is an opal that has lost 
color and brilliancy by reason of the 
evaporation of its water. If placed in 
water or alcohol, this stone becomes trans- 
parent, only to lose this quality when the 
water or alcohol has evaporated. 



PEARL, ft 

The hydrophane becomes transparent 
more quickly in warm than in cold water, 
but most rapidly in alcohol. If boiled in 
oil, the hydrophane is said to retain its 
brilliancy for years. 

The cachelong is milky-white, and 
nearly opaque, and is found in small 
masses in the river Cach, in Bucharia, 
and also in Iceland. 

Although one of the most magnificent 
of the gem stones, the opal for many 
years was under the ban of superstition. 
Now, this splendid stone once more com- 
mands a foremost place in the jewelers' 
art, and the opal mines of Hungary and 
Queensland are being worked to their 
fullest extent to supply the demand. 

Pearl. 

Although an organic product, the pearl 
is always ranked amongst the most 
precious of gems, and is distinguished by 
being the only gem that does not require 
the lapidary's touch to bring out its 
beauties. 



?2 PRECIOUS STONES. 

Ancient writers have accounted for the 
origin of pearls by saying that they were 
formed of angels' tears, or drops of dew 
from heaven, which, during the midsum- 
mer nights, fell into the gaping mouths of 
the pearl-oysters. 

According to modern scientific investi- 
gation, the formation of the pearl does 
not seem to be the result of healthy 
natural causes, but comes from the efforts 
of the oyster to rid itself of some foreign 
substance, like a grain of sand, a bit of shell 
or vegetation, or some unwelcome visitor 
in the shape of a small water insect. 

When annoyed by an intruding sub- 
stance, the oyster begins to deposit its 
nacre, or mother-of-pearl, in regular con- 
centric layers around the intruder, these 
layers gradually increasing in circumfer- 
ence and forming the pearl. Thus, like 
an onion, the pearl is merely a succession 
of layers or skins, starting from a small 
core, or nucleus, which is always present, 
though often only of microscopical size. 



PEARL. 73 

Pearls have sometimes been found 
where the outer layer, or skin, as it is 
technically called, has been discolored or 
otherwise injured, and when this top skin 
has been carefully removed the result was 
a somewhat smaller but perfect pearl. 

This, however, is a very delicate opera- 
tion, and at the pearling grounds is only 
resorted to by men of experience. The 
composition of the pearl is carbonate of 
lime, with a small proportion of organic 
matter, and the specific gravity 2.5 to 
2.7. 

The pearl is affected by acids, and is 
easily calcined on exposure to heat. 

In color, the pure white, slightly trans- 
parent, is the most highly prized ; while in 
India and China the bright yellow colors 
are sought after. 

Decided colors, however, such as black, 
pink, and golden-yellow bring a high 
price, and, in fact, black pearls, if perfect 
in color and shape, are at present more 
valuable than any other kind. 



74 PRECIOUS STONES. 

The beauty and value of a pearl de- 
pend on form, quality of texture or skin, 
color, transparency or water, and lustre or 
orient. 

In form, the perfectly round shape comes 
first in value, then a finely formed drop or 
pear shape, and lastly the oval or egg shape. 

Pearls that are flat on one side and 
rounded on the other are called boutons 
or button pearls. These are frequently 
found attached to the shell, and are cut 
out and the bottom part smoothed and 
polished. 

It is easy, however, to detect this class 
of pearls by the lack of pearly lustre on 
the side that was attached to the shell. 

When a pearl is rough and odd-shaped 
it is called a baroque, and some extremely 
fantastic shapes are found, especially in 
fresh-water oysters. 

The texture or skin of a fine pearl 
should be perfectly smooth and free 
from all spots, indentations, wrinkles, or 
scratches. 



PEARL. 75 

Pure white is the desirable color for 
a gem pearl, but many others that are 
slightly tinted with blue, pink, or yellow 
will pass for gems if they are otherwise 
perfect. 

The transparency or " water " of a 
pearl, while not existing in fact, is still 
one of the requisites of a fine pearl ; there 
must be an appearance of transparency, 
which adds to the beauty of the gem. 

To describe the lustre or orient of the 
pearl, the author can only use the term 
pearly, as there is no other substance that 
approaches the brilliancy and color of a 
pearl, excepting, of course, mother-of- 
pearl — the nacre in the pearl-oyster. 

Without orient or lustre, the pearl of 
finest form and color has but little value. 

Lustre is to the pearl what brilliancy is 
to the diamond ; when the orient is ab- 
sent there is no life, no beauty. 

Pearls are principally supplied by two 
groups of pearl-oysters or mussels : the 
marine or meleagrina margaritifera, a 



j6 PRECIOUS STONES. 

round-cornered square shell with very 
thick sides, measuring six to eight inches 
in length. 

The color of this shell is mostly black- 
ish-green, but it is also sometimes yellow- 
ish ; the edges of the inner part of the 
shell are black, but the rest of the interior 
is the beautiful mother-of-pearl. 

The oyster itself is small for the size of 
the shell. 

This specimen is found on the coast of 
Ceylon, Persian Gulf, Japanese, Mexi- 
can and California coasts, the western 
shores of South America, Brazil, West 
Indian Islands, Panama, Sooloo Archi- 
pelago, and the northeast and northwes- 
tern coast of Australia. 

The fresh-water or unio margaritifera 
is an even, egg-shaped mussel found in 
brooks, rivers, and lakes in temperate 
zones in nearly all parts of the world. 

Some fine river pearls have been found 
in the United States, but most of the 
American pearls are of a button or elon- 



PEARL. 77 

gated shape, or are baroques or fancy- 
shaped. 

In China many people engage in the 
business of making small pellets of clay 
or metal images, which in the month of 
May are introduced into the river mussels 
(mytilus cygneus). 

The mussels are replanted, and in No- 
vember they are taken up again. Some 
of the oysters die, but most of them are 
found to have been actively at work cov- 
ering the little pellets or metal figures 
with nacre, and while no strictly first-class 
pearls are formed in this way, many curious 
little pearl figures or gods are made and 
sold to the curious or devout. 

Pink or conch pearls are found in the 
Gulf of California and coasts of Mexico, 
Bahama Islands, West Indian Islands, and 
in some rivers in South America. 

They seldom occur in regular shapes, 
and although they are termed pink pearls, 
they range in color from red to pale yellow, 
and are often found of a china-white color. 



78 PRECIOUS STONES.. 

The pink pearl displays a wavy appear- 
ance and a peculiar sheen, something like 
watered silk. As the pink pearl is seldom 
found perfectly round and of a good color, 
such a specimen is very valuable. 

Chrysolite. 

The chrysolite, peridot, and olivine dif- 
fer in color, but are practically of the same 
composition. 

The chrysolite proper is of a pale green- 
ish-yellow color, the peridot a deep olive- 
green, and the olivine of a yellowish or 
light olive-green color ; these stones also 
shade into brown. They crystallize on 
the rhombic system, are tranparent to 
translucent, 6.5 to 7. in the scale of hard- 
ness, and 3.3 to 3.5 in specific gravity. 

The cleavage is distinct, fracture con- 
choidal, refraction double, and lustre 
vitreous, and in the olivines somewhat 
greasy. 

These stones are easily affected by sul- 
phuric acid; but are infusible before the 



CHR YSOLITE. 79 

blow-pipe, excepting some kinds contain- 
ing much iron. 

With borax, they melt to a pale-green 
transparent glass. 

Chrysolites are composed of silica, 
magnesia, and oxide of iron. 

Perfectly crystallized chrysolites are 
brought from Constantinople, but the 
exact locality where they are found is 
unknown. 

Less distinct specimens occur at Vesu- 
vius, Mexico, the isle of Bourbon, Au- 
vergne, Egypt, Natolia, Brazil, Germany, 
Pegu, Ceylon, Switzerland, and North 
America. 

Peridots are distinguished by being the 
only precious stones that have literally 
dropped from heaven, as they have been 
found in meteorites. 

The Oriental chrysolite of commerce is 
true chrysoberyl, and is harder and 
heavier than chrysolite, and the stone 
called Ceylon chrysolite is a greenish- 
yellow tourmaline, which is easily dis- 



80 PRECIOUS STONES. 

tinguished, as it is also harder while con- 
siderably lighter than the chrysolite. 

The green garnet is of a pronounced 
green color, and is harder and heavier 
than the olivine or chrysolite. Although 
suitable for mounting in brooches and 
other ornaments, these stones are not 
sufficiently hard for the rough usage as 
ring-stones. 

Garnet. 

Almandine, almandite, Syrian garnet, 
essonite, cinnamon-stone, pyrope, Bohe- 
mian garnet, vermeille, Cape garnet, Cape 
ruby, Arizona ruby, American ruby, car- 
buncle, uwarowite, demantoide, grossula- 
rite, and Bobrowska garnet are some of 
the scientific and commercial names for 
different species and colors of the garnet 
group. 

The crystallization of the garnet is iso- 
metric, refraction single, specific gravity 
3.15 to 4.3, hardness 5 to 8, lustre vitreous, 
fracture uneven, colors red, violet, brown, 



GARNET. 8 1 

yellow, green, and white, and the various 
shadings of these colors. 

Most varieties fuse easily to a brown or 
black glass ; the uwarowite fuses with 
borax to a clear chrome-green glass. 

Syrian, almandine, almandite, and car- 
buncle are different names for the iron- 
alumina garnet. 

In colors, these stones shade from deep- 
red to violet and brownish-red, and are 
composed of : 

Silica 36.01 

Alumina 20.06 

Protoxide of iron . . . 43.03 

The specific gravity is 4. to 4.2, and 
hardness 7.5. 

This garnet, sometimes called the 
precious garnet, is found in Ceylon, Pegu, 
Brazil, Greenland, Hindustan, Bohemia, 
Tyrol, GEtzthal, Carinthia, Styria, Switz- 
erland, Ariolo, Canada, Maggia, Hungary, 
Sweden, Norway, Scotland, Spain, and 
the United States. 



82 PRECIOUS STONES. 

Grossularite, or lime-alumina garnet, is 
known in commerce as essonite, or cinna- 
mon-stone. The color is yellow, of various 
shades ; specific gravity 3.5 to 3.65, and 
hardness 6.5. 

These stones are sometimes sold for 
jacinths, but they are softer than the 
jacinth, and melt easily before the blow- 
pipe. Essonites come principally from 
Ceylon, but are also found in other places. 

Pyrope or Bohemian garnet is the mag- 
nesia-alumina variety, and is of a uniform 
dark blood-red color. This stone is found 
in Bohemia, and although quantities of 
small pieces are found, large specimens 
are rare, and a piece that will cut into 
a four- or five-carat stone is seldom met 
with and commands a high price. 

These garnets are found at Stiefelburg 
by Meronitz, Triblitz, Podsedlitz, and 
Neupaka. 

The pyrope turns black under the blow- 
pipe, then red again, and melts with diffi- 
culty into a black glass. With borax it 



GARNET. 83 

melts to an emerald-green glass. The 
specific gravity of this garnet is 3.69 to 
3.78, and hardness 7.5. 

Vermeille is a name given to the orange- 
red almandine, Cape garnet to the bright 
red-yellow variety, Cape ruby to the pyr- 
ope, and American ruby tc the blood-red 
kind found in New Mexico, Montana, and 
Arizona. Carbuncle is a term applied to 
all garnets cut with a smooth rounding 
top, sometimes called, after the French, 
cabochon. 

Uwarowite or lime-chrome garnet is one 
of the rarest and most beautiful of the 
garnet group. 

The color of this stone is emerald-green, 
hardness 7.5, and specific gravity 3.41 to 
3.52. Uwarowites are found near Bissersk 
in the Urals of Russia, but rarely in speci- 
mens of sufficient size to cut into gems. 

This garnet is heavier and harder than 
the true emerald. 

Demantoide or Bobrowska garnet is a 
soft garnet, olive-green to brown and 



84 PRECIOUS STONES. 

blackish-green in color, sometimes light 
green. It is found in the Bobrowska 
River in the Urals. The specific gravity 
is 3.85, and hardness about 6, its softness 
making it undesirable for many ornaments. 
Before the blow-pipe it fuses into a black 
bead. 

These garnets are often sold as olivines ; 
they are heavier than olivines and softer. 

Demantoide is composed of : 

Silica . 35.44 

Lime 32.85 

Sesquioxide of iron . . 32.85 

Magnesia .20 

Topaz. 

Topaz belongs to the rhombic system 
of crystallization. Its cleavage is basal 
and perfect, fracture uneven, hardness 8, 
scratching quartz distinctly, specific grav- 
ity 3.4 to 3.6, lustre vitreous, refraction 
double, and colors ranging from colorless 
or white to bluish-white, light blue, wine- 
yellow, straw-yellow, golden-yellow, green- 
ish- and pale-red to pink. 



TOPAZ. 85 

Topaz becomes electric from rubbing 
or pressure, and retains electricity for 
twenty-four hours. Before the blow-pipe 
topaz partly loses color, but does not melt, 
and with borax it fuses slowly to a white 
bead. 

Topaz is partially attacked by sulphuric 
acid, and dissolves in salts of phosphorus. 

The composition of topaz is : 

Silicon 15.05 

Aluminium 30.02 

Oxygen 36.08 

Fluorine 17-05 

Goutte d'eau or colorless topaz, some- 
times called " slaves diamond," Siberian 
or bluish-white, Brazilian or golden to 
reddish-yellow, Saxony or pale-wine yel- 
low, Brazilian ruby or pink, Brazilian 
sapphire or light blue, and aquamarine or 
greenish, are the various commercial names 
for topaz. 

Most of the Brazilian rubies or pink 
topazes are produced by heating the red- 
dish or dark-yellow variety, either in a 
crucible or by enveloping the stone in 



86 PRECIOUS STONES. 

German tinder and setting fire to the tin- 
der. If heated too much, the stone is apt 
to become colorless, and if suddenly cooled 
it may crack. 

Colorless or white topaz takes a very 
high polish, and is wonderfully clear and 
transparent. 

The great Portuguese diamond, " The 
Braganza," of about 1,680 carats, is sup- 
posed to be a white topaz. 

Topaz is found in the Urals, Kam- 
schatka, Alabaschka, Miask, Nestschinsk, 
Adun Tschilon, Villa Rica, Boa Vista, 
Capao, Lana, Minas Novas, Cairngorm 
Mts., Schlackenwald, Zinnwald, Schneck- 
enstein, Ehrenfriedensdorf, Altenburg, 
Orenburg, Mourne Mts. — Ireland, Aus- 
tralia, New South Wales, Ceylon, Mexico, 
and the United States. False topaz, or 
the ordinary topaz of commerce, is yellow 
quartz resembling yellow topaz, but lack- 
ing its brilliancy and hardness ; it is also 
very much lighter, being only 2.5 to 2.7 
in specific gravity. 



APA TITE. 87 

Beryl and chrysolite are often mistaken 
for topaz, but as they are softer and beryl 
is much lighter, they are easily distin- 
guished from the topaz. The strong elec- 
tric property of the topaz is also a con- 
clusive test. 

Oriental topaz, or yellow corundum, is 
harder and heavier than the occidental or 
true topaz. 

Apatite. 

Apatite, which is seldom used as a gem 
stone, sometimes resembles the beryl and 
emerald, but is much softer and rarely has 
the color and brightness combined of the 
former gems. 

This mineral, composed principally of 
subsesquiphosphate of lime, is 4.5 to 5. in 
hardness, has the specific gravity of 2.95 
to 3.25, is transparent to opaque, vitreous 
in lustre, infusible before the blow-pipe, 
and dissolves slowly in nitric acid. In 
colors, apatite varies from colorless to sea- 



88 PRECIOUS STONES. 

green, bluish-green, violet-blue, gray, yel- 
low, red, and brown. 

Apatite is found in Saxony, the Hartz 
Mts., Bohemia, Norway, Bavaria, England, 
St. Gothard in Switzerland, and in the 
United States. 

Felspar. 

Four varieties of felspar are used as gem 
stones — moonstone or orthoclase, sun- 
stone or avanturine felspar, Amazon stone 
or green felspar, and Labrador or Labrador 
spar. 

Moonstone. 

This variety of felspar is called ortho- 
clase, adularia, and orthose, besides the 
commercial names of fish-eye, Ceylon or 
water opal, and in the yellow and red tints 
sunstone. Moonstone occurs in crystals 
and crystalline fragments, also massive and 
granular; its hardness is 6. to 6.5, specific 
gravity 2.4 to 2.6, refraction double, is not 
attacked by acids, and is composed of : 



MOONSTONE. 89 

Silica 64.5 

Alumina 18.5 

Potash 17. 

With traces of soda. 

This beautiful stone is the clearest of all 
varieties of felspar. It is colorless, or only 
slightly tinted with blue, green, yellow, 
and flesh-red, and is transparent to trans- 
lucent. 

The lustre is vitreous, and a brilliant 
pearly streak of white light plays from 
side to side. 

The yellowish- and reddish-tinted speci- 
mens are called sunstones, and are quite 
rare. These sunstones must not be con- 
founded with the avanturine or felspar 
sunstone. 

Moonstones are found principally in 
Ceylon and on the St. Gothard in Switzer- 
land, but also occur in Bavaria, Green- 
land, Tyrol, Dauphine, Norway, and the 
United States. 

During the past few years, large quanti- 
ties of moonstone balls, cut like whole 
pearls, have been used for jewelry — the 



90 PRECIOUS STONES. 

stones being much sought as well because 
of their beauty as on the ground of the 
popular superstition that they will bring 
good luck to the wearer. 

Small pieces or balls are not very valu- 
able, but large perfect specimens command 
a good price. 

SUNSTONE. 

(AVANTURINE felspar.) 

Sunstone or avanturine felspar is a 
variety of oligoclase ; grayish-white to 
reddish-gray in color, usually the latter ; 
containing minute crystals of hematite, 
gothite or mica, which are imbedded and 
scattered through the stone, and give 
forth golden-yellow, reddish, or prismatic 
reflections. The hardness is 6 to 7, spe- 
cific gravity 2.56 to 2.72, and lustre pearly 
or waxy to vitreous. 

Sunstones are found near Stockholm, 
in Finland, the Urals, Ceylon, the Alps, 
Iceland, the United States, and other 
places. 



amazon stone. 9 1 

Amazon Stone. 

(green felspar.) 

The Amazon stone is a green variety of 
felspar, which was first found on the 
banks of the Amazon River, but now 
comes from Siberia and the United States. 
This stone consists of potash, alumina, 
and silex — is green in color but rarely 
clean, being discolored in places and 
usually covered with small white spots. 

The Amazon stone is harder than glass, 
but is scratched by rock crystal. Its 
specific gravity is 2.5 to 2.6 ; acids do not 
affect it, and it melts with difficulty before 
the blow-pipe. 

Labradorite. 

Labrador stone or labradorite is some- 
times known as opaline felspar, and was 
first discovered on the island of St. Paul 
on the coast of Labrador. 

Labradorite is translucent to opaque, 
gray-green or brown in color, and has 



92 PRECIOUS STONES. 

beautiful chatoyant reflections of brilliant 
blue, sea-green, and sometimes red and 
yellow, changing from one color to another. 
Labradorite is 6 in hardness, has a specfiic 
gravity of 2.62 to 2.76 ; a vitreous to 
pearly lustre, is brittle, fuses with difficulty 
before the blow-pipe, and is decomposed by 
muriatic acid. It is composed of : 



Silica . . . 


. • 52.9 


Alumina . . 


• • 30.3 


Lime . . . 


. . 12.3 


Soda .... 


• • 4-5 



Large masses of this stone are found on 
the coast of Labrador. It is also found 
in Finland, Russia, and the United States. 
Because of the dark chatoyant appearance 
the name of ceil de bceuf or ox-eye is 
sometimes applied to labradorite. Hand- 
some specimens, cut cabochon, form pretty 
ring stones, and many effective engraved 
cameos have been produced by using the 
bright portion for the relief work and the 
gray dead part for the base. 



CYANITE. 93 

Cyanite. 

This stone is the transparent variety of 
disthene, and is sometimes commercially 
known as sappare. Cyanite is colorless to 
bluish-white, sky-blue, berlin blue, yellow- 
ish- and reddish-white, gray, and green. 

The hardness is 5 to 7, specific gravity 
3.45 to 3.70, lustre vitreous and pearly; 
it is infusible before the blow-pipe, but 
fuses with borax ; is not attacked by acids, 
and is composed of : 

Silica 36.8 

Alumina .... 63.2 

Cyanite is found in Switzerland, the 
Tyrol, Styria, Carinthia, Bohemia, Nor- 
way, Finland, France, South America, 
Scotland, Ireland, Siberia, the East Indies, 
and the United States. Clean specimens 
are not plentiful, and fine blue pieces have 
frequently been sold for sapphires. The 
cyanite can be distinguished from the 
sapphire by its inferior hardness and 
lighter weight. 



94 precious stones. 

Lapis Lazuli. 

Lapis lazuli, the sapphire of the ancients, 
is a mineral, translucent to opaque, ranging 
in color from colorless to an azure-blue, 
violet-blue, green, and red. 

The principal color, however, is a rich, 
azure blue, sometimes shading into green, 
and having a vitreous to greasy lustre. 

Its hardness is 5 to 5.5, specific gravity 
2.38 to 2.42 ; it is decomposed by muri- 
atic acid, and fuses before the blow-pipe to 
a white glass. It is rarely found clean, but 
has usually a number of veins and spots 
of a metallic nature. It is composed of : 

Silica 45. 

Alumina . . . . 31.76 

Soda 9.09 

Lime 3.52 

Sulphuric acid . . 5.89 
and traces of iron, soda, and potash. 

This mineral is found in Siberia, Tran- 
sylvania, Persia, China, Thibet, Tartary, 
South America, India, and Brazil. 

Lapis lazuli is sometimes employed for 
jewelry, and was for some centuries ground 



HIDDENITE. 95 

up and used to make the mineral paint 
known as genuine ultramarine. This paint 
is now produced chemically, and the more 
costly mineral compound is rarely used. 

The imitation of lapis lazuli for jewelry 
purposes is also very easy, as metal filings 
can be readily introduced into the azure 
blue glass, and thus an imitation of the 
genuine stone produced, which is perfect 
excepting in hardness. 

HIDDENITE. 

The hiddeniteis a variety of spodumene 
that has only been found in one locality, 
namely, Alexander County, North Caro- 
lina.' This mineral was discovered by W. 
E. Hidden, and has been named after him. 

The hiddenite is perfectly transparent, 
and varies from a pale yellowish- to a deep 
emerald-green, being very brilliant, and 
approaching the emerald in color. As this 
stone is rarely found large enough for cut- 
ting into gems, it is highly prized, and 
good specimens command a large price. 



g6 PRECIOUS STONES. 

The hardness of the hiddenite is 6.5 to 
7, and specific gravity 3.13 to 3.19; before 
the blow-pipe it melts to a clear glass, and 
it is attacked by salts of phosphorus. It 
is composed of: 

Silica 64.35 

Alumina .... 26.58 

Lithia 7.05 

with traces of iron and soda. 

Spodumene. 

Spodumene is sometimes cut and pol- 
ished as a gem, but its peculiar cleavage 
makes it a bad stone for the lapidary to 
cut and the jeweler to mount. 

Its hardness is 6.5 to 7, specific gravity 
3.13 to 3.19, and lustre, vitreous to pearly. 

Grayish - green, greenish - white, and 
sometimes yellow or faint red are the 
colors. Its composition is : 

Silica 64.2 

Alumina .... 29.4 
Lithia 6.4 

Acids do not attack spodumene, and un- 
der the blow-pipe it fuses to a white glass. 



DICHROITE. 97 

This mineral is found in Sweden, the 
Tyrol, Ireland, Scotland, and the United 
States. 

DICHROITE. 

Dichroite is sometimes known under 
the mineralogical names of cordierite and 
iolite, and commercially as saphir d'eau, 
or water sapphire. This stone is remarka- 
ble for pleichroism, sometimes showing 
three different colors in as many direc- 
tions, and when properly cut has often 
the star formation of the corundum star- 
stones. 

Water sapphire, as the blue specimens 
are called, is 7 to 7.5 in hardness, specific 
gravity 2.56 to 2.67, transparent to trans- 
lucent, and frequently full of flaws. It is 
partially decomposed by acids, melts with 
difficulty before the blow-pipe, is vitreous 
to greasy in lustre, and is composed of : 



Silica .... 


• 49- 


Alumina . . . 


• 32. 


Ferrous oxide 


• 7- 


Magnesia . . 


• 9- 



98 PRECIOUS STONES. 

Besides the saphir d'eau, which is blue, 
dichroite occurs colorless, bluish-white, 
yellowish-white, yellowish-gray to yellow- 
ish-brown, indigo to blackish-blue, and 
violet. This mineral is found in Ceylon, 
Spain, Norway, Sweden, Tuscany, Green- 
land, and Bavaria. Sapphire is harder 
and much heavier than dichroite. 

IDOCRASE. 

Idocrase or vesuvianite was first found 
amongst the ancient ejections of Vesuvius, 
and it is still found at Vesuvius in hair- 
brown to olive-green colors. 

Vesuvianite is 6.5 in hardness, 3.35 to 
3.45 in specific gravity, transparent to 
opaque, lustre vitreous to greasy. It pos- 
sesses strong double refraction, is attacked 
by acids, and melts readily under the 
blow-pipe. Vesuvianite consists of: 



Silica .... 


37-75 


Alumina . . . 


17.23 


Sesquioxide of iron 


4-43 


Magnesia . . . 


3-79 


Lime .... 


37-35 



EUCLASE. 99 

In colors, this mineral shades from 
brown to black, yellow, pale-blue, and 
green, and it is found at Vesuvius, Alps, 
Piedmont, Mt. Somma, Etna, Norway, 
Sweden, Spain, Hungary, Urals, and the 
United States. 

Transparent or strongly translucent 
specimens, in handsome green or brown 
varieties, are used for jewelry, principally, 
however, in Turin and Naples. 

Chrysolite and green garnet are some- 
times substituted for vesuvianite. The 
first has a greater specific gravity and is 
more vivid in color, and the latter is also 
heavier and harder. 

EUCLASE. 

Euclase is very brittle, and therefore is 
rarely used as an ornamental stone. 

This mineral has the hardness of 7.5 ; 
specific gravity, 3.1 ; lustre, vitreous to 
pearly ; it is transparent to semi-trans- 
parent, doubly refractive, is not acted 
upon by acids, fuses under the blow-pipe 
to a white enamel, and is composed of : 



100 PRECIOUS STONES. 



Silica . . . 


. . 41.2 


Alumina 


• • 35-2 


Glucina . . . 


• • 17.4 


Water . . . 


. . 6.2 



Euclase occurs in Brazil, in the neigh- 
borhood of Villa Rica, and also in the 
Urals, in colorless, pale green, blue, pale 
yellow, and white colors. 

Sphene. 

Sphene or titanite is also a brittle 
mineral, 5 to 5.5 in hardness; specific 
gravity, 3.4 to 3.56; transparent, doubly 
refractive ; lustre, adamantine to resinous ; 
colors, brown, gray, yellow, green, black, 
and colorless ; and composition : 

Silica 31 

Titanium oxide ... 41 

Lime 27 

Ferrous oxide ... 1 

When transparent in colorless, green- 
ish, or yellow colors, this mineral presents 
an appearance like the fire opal. 

Sphene is found in Switzerland, the 



PHENAC1TE. 101 

Urals, Tyrol, Finland, Wales, Ireland, 
Germany, Canada, and the United States. 

PHENACITE. 

This mineral, rarely used as a gem 
stone, is 7.5 to 8 in hardness ; specific 
gravity, 2.96 to 3 ; lustre, vitreous ; trans- 
parent to semi-translucent, doubly refrac- 
tive, it does not melt before the blow-pipe, 
and contains : 

Silica 54.2 

Glucina 45.8 

Phenacite occurs colorless, and also 
bright wine-yellow inclining to red, and 
brown. This stone is found in Russia, 
Mexico, and Alsace. 

The colorless or transparent variety ap- 
proaches the diamond in brilliancy, espe- 
cially under artificial light. 

Epidote. 

Epidote usually occurs in a peculiar 
yellowish-green, called pistachio green, a 
color that is seldom found in other min- 



I02 PRECIOUS STONES. 

erals. Besides this color, olive, brown- 
ish-green, greenish-black and black, red, 
yellow-gray, and grayish-white occur. 
The hardness of epidote is 6 to J\ 
specific gravity, 3.32 to 3.50; lustre, vit- 
reous to pearly ; refraction, double. The 
stone is transparent to opaque, is at- 
tacked by acids, and is slightly affected 
by the blow-pipe. It is composed of : 



Silica . . 
Alumina . 
Ferric oxide 
Lime . 
Water . . 



33 
22 
15 

23 
2 



Epidote is found in Norway, Saxony, 
Siberia, Brazil, on the St. Gothard, in 
Switzerland, in the Tyrol, and in the 
Hartz. 

AXINITE. 

Axinite is a brittle mineral which has 
occasionally furnished some pretty gem 
stones. 

The hardness of this stone is 6.5 to 7; 
specific gravity, 3. to 3.3 ; lustre, vitreous. 
It is transparent to translucent, is not at- 



D 10 P SIDE. 103 

tacked by acids, and melts readily before 
blow-pipe. It is composed of : 

Silica 43 

Lime 20 

Alumina 16 

Ferric oxide . . . . . 10 

Borontrioxide .... 5 

Manganese dioxide . . 3 

Magnesia 2 

Potash 1 

Axinite occurs in clove-brown, plum- 
blue, and pearl-gray, and exhibits trichro- 
ism. The best specimens come from St. 
Christophe in Dauphiny, but it is also 
found at Santa Maria, and in Switzer- 
land, Sweden, England, Chili, Saxony, the 
Hartz Mountains, and the United States. 

Axinite is usually cut, like the opal, 
cabochon, but is rarely used as a gem 
stone. 

DlOPSIDE. 

Diopside is cut and sometimes sold in 
Turin and in Chamouny as a gem stone, 
but no great quantity of this mineral is 
used for ornamental purposes. 



104 PRECIOUS STONES. 

The hardness of diopside is 5 to 6 ; spe- 
cific gravity, 2.9 to 3.5 ; lustre, vitreous to 
greasy. It is transparent to translucent, 
brittle, cannot be dissolved by acids, and 
melts before the blow-pipe. It is com- 
posed of : 

Silica ..... 54 

Lime .... 24 

Magnesia . . . 18 

Ferrous oxide . . 4 

This mineral is grayish-white to pearl- 
gray, and greenish-white to greenish-gray. 
The best green transparent specimens are 
from the Mussa Alp and Zillerthal, but it 
is also found in the Urals and the United 
States. 

Fluor Spar. 

This mineral occurs in many colors, 
often approaching the finer gems in ap- 
pearance, and bearing the commercial 
names of false ruby, false emerald, false 
topaz, etc., etc., according to its color. 

Fluor spar is brittle, 4 in hardness, has 
the specific gravity of 3.1 to 3.2, single 



HYPERSTHENE. 105 

refraction, is transparent to translucent, 
has a vitreous lustre, phosphoresces when 
heated, is attacked by acids, and melts 
before the blow-pipe. It is composed of : 

Fluorine . . 48.7 
Calcium . . 51.3 

White, yellow, green, rose- and crimson- 
red, violet-blue, sky-blue, and brown, wine- 
yellow, greenish-blue, and gray are the 
colors of this many-tinted mineral. 

Fluor spar is found in England, Nor- 
way, Baden, Nova Scotia, Thuringia, the 
Alps, Saxony, and the United States. 

Large pieces of this mineral are made 
into beautiful vases and ornaments. 

HYPERSTHENE. 

Handsome specimens of hypersthene or 
Labrador hornblende are used for orna- 
mental purposes. 

This mineral is found in crystalline 
masses, has the hardness of 6, specific 
gravity 3.3 to 3.4, lustre pearly to metal- 
lic. It is translucent to opaque, brittle, 



I06 PRECIOUS STONES. 

and fuses before the blow-pipe. It con- 
sists of : 

Silica ..... 54.2 
Magnesia . . . . 24.1 
Protoxide of iron . . 21.7 

Hypersthene occurs in dark-brown, 
green, grayish-black, greenish-black, and 
jet-black colors, and is found in the isle 
of Skye, the Hartz Mountains, Saxony, 
Labrador, Greenland, Norway, Sweden, Bo- 
hemia, Thuringia, and the United States. 

Quartz. 

The quartz group is the largest and 
most diversified among precious stones. 
Quartz occurs massive, in concretions, and 
in confused crystalline masses. 

On account of the abundance of the 
massive kinds, such as jasper, agates, 
onyx, etc., some writers place the quartz 
group under the head of semi-precious 
stones, and lately the United States customs 
authorities have gone further in that 
direction, and have ruled that "because 



QUARTZ. 107 

of the abundance and comparative cheap- 
ness of agates, onyxes, etc., they were no 
longer precious stones." This position, 
however, the custom-house speedily aban- 
doned, and, for dutiable purposes at least, 
the quartz family, in all its ramifications, 
is recognized as belonging to the precious 
stones. 

Harder than the tourmaline, turquois, 
or opal, as hard as the chrysolite, and 
nearly as hard as the garnet or emerald, 
there is no reason why the crystallized 
varieties, such as amethyst, cairngorm, 
false topaz, chrysoprase, and even the 
cat's-eye and finer onyxes, should not be 
classed among the precious stones. 

Some more plentiful and less beautiful 
varities of quartz are not valuable, and 
they take the same position in the quartz 
family that the huge imperfect crystals do 
in the beryl group. Whenever the speci- 
men is sufficiently beautiful to be cut and 
polished for setting in jewelry, it should 
be included under the precious stones. 



108 PRECIOUS STONES. 

Quartz crystallizes in the rhombohedral 
system, and many varieties are found mas- 
sive and compact. The cleavage is indis- 
tinct but can sometimes be found by 
plunging a heated crystal into cold water. 
The hardness of quartz is 7 ; specific grav- 
ity 2.5 to 2.8, the purest kinds being 2.65 ; 
the lustre is vitreous to resinous, and 
fracture conchoidal. 

Quartz is tough, brittle, and feels cold ; 
it becomes positively electric by rubbing, 
shows phosphorescence in the dark, and 
gives sparks if struck with another piece 
of quartz or with steel. 

Quartz is transparent to translucent, 
semi-translucent to opaque, doubly re- 
fractive, and does not melt before the 
ordinary blow-pipe, but may be melted 
with the oxyhydrogen blow-pipe. It also 
melts with soda to a clear glass, and is 
soluble in fluohydric acid. 

Quartz is composed of pure silica 

Oxygen . . 53 
Silicon . . 47 



CRYSTALLIZED QUARTZ. IO9 

Some of the impure varieties contain 
oxide of iron, carbonate of lime, clay, and 
other minerals. 

Crystallized Quartz. 

Colorless quartz or pure rock-crystal is 
found in many parts of the world, notably 
in Switzerland, Dauphiny, Piedmont, the 
Carrara quarries in Italy, Canada; in 
Herkimer County, New York, and on the 
shores of Lake George, in the same place ; 
at Hot Springs, Arkansas; and along 
the beach of Long Branch, Cape May, 
and many other places. 

Rock-crystal, commercially known as 
Bohemian diamond, occidental diamond, 
Lake George diamond, rhinestone, pebble, 
etc., etc., is colorless and transparent. 
This stone is largely used for optical pur- 
poses, and is also sometimes cut into brill- 
iants to imitate the diamond. 

While rock-crystal is considerably harder 
than strass or paste, it lacks, however, the 
brilliancy of the fine-composition imitation 
diamond. 



110 PRECIOUS STONES. 

Besides being much softer, the paste is 
often heavier than the crystal, because of 
the quantity of lead and other minerals 
used in its composition. 

Amethyst. 

Amethystine quartz or amethyst varies 
in color from light to clear-dark purple, 
sometimes nearly black, and from light to 
dark bluish-violet. The coloring of the 
stone is supposed to be due to manganese. 

The best amethysts come from Brazil 
and Ceylon, but good specimens are found 
in India, Persia, Botany Bay, Transylvania, 
near Cork and the island of May in Ireland, 
at Oberstein, in Saxony, in Hungary, 
Siberia, Nova Scotia, Sweden, Bohemia, 
Canada, and in the States of Maine, Penn- 
sylvania, Colorado, Georgia, Virginia, and 
Michigan. 

Under heat, the amethyst turns first 
yellow, then green, and finally becomes 
colorless. The value of an amethyst de- 
pends upon the fashion, and the time has 



YELLOW QUARTZ. Ill 

been when these stones ranked among the 
most valuable of precious stones. At 
present, a fine amethyst can be bought 
for very little money, but should the stone 
become fashionable again, the best speci- 
mens will command good prices. 

Yellow Quartz. 

Yellow quartz, known as false topaz, 
Bohemian, occidental, Indian, or Spanish 
topaz, resembles the real topaz in color, 
but is softer, lighter, different in crystal- 
lization and cleavage, and in electrical 
properties. 

In color, this stone varies from the light- 
est yellow to orange-red and brown. 

Most of the yellow quartz comes from 
Brazil, and much of it is changed to yellow 
by burning amethyst and smoky quartz. 

Cairngorm, etc. 

Smoky yellow to smoky brown, often 
gray and black, are the tints of the cairn- 



112 PRECIOUS STONES. 

gorm. This species of transparent quartz 
takes its name from Cairngorm in Inver- 
nessshire, in Scotland, a locality where 
some of the best specimens have been 
found. Pike's Peak, Arkansas, and certain 
districts in North Carolina have also pro- 
duced some very fine smoky topazes. 

The cairngorm is used for seals, beads, 
and some of the cheaper jewels, and is 
largely sold at watering-places in Switzer- 
land, and in the Western United Sates. 

The stone is very popular in Scotland. 
Hair or needle stones is the name given 
to these varieties of crystallized quartz 
when they contain foreign substances, 
such as rutile, manganese, chlorite, etc., in 
hair or needle formation. 

These stones are cut to represent the 
needle enclosures in an upright position, 
and are called sagenite or Venus hair 
stones or love arrows. 

Iridescent or rainbow quartz is the 
variety of rock-crystal containing cracks 
and fissures which reflect all the colors of 



ROSE QUARTZ. 113 

the rainbow. Quartz can also be artifi- 
cially colored by rapidly cooling a heated 
specimen and then dipping the piece into 
a coloring preparation ; the minute cracks 
in the quartz absorb the coloring matter, 
and the result is a red-, blue-, or green- 
tinted stone. 

The massive varieties of quartz embrace 
the rose quartz, avanturine, cat's-eye, cro- 
cidolite, heliotrope, chrysoprase, prase, 
plasma, chalcedony, agates, onyx, car- 
nelian, jasper, hornstone, and flint. 

Rose Quartz. 

Rose quartz occurs in a massive form, 
usually very imperfect and cracked, and 
varying in color from rose-red to pink. 
The color is supposed to be due to titanic 
acid, and often becomes paler on exposure. 

This stone is nearly opaque and semi- 
transparent on the edges, has a greasy 
lustre, and specific gravity of 2.65 to 2.75. 
Rabenstein near Zwiesel in Bavaria, the 



114 PRECIOUS STONES. 

United States, Brazil, France, Ceylon, 
Finland, and Siberia are places where rose 
quartz has been found. 

AVANTURINE. 

Avanturine is an opaque, yellow, brown, 
or red quartz, spangled with minute scales 
of mica or some other mineral, and found 
principally near Madrid, in Spain. It is 
also found in France, Scotland, Bavaria, 
the Urals, and Styria. 

A beautiful imitation of avanturine, 
called goldstone, is manufactured of glass 
into which metal filings are introduced. 
This goldstone is superior to avanturine 
in every point except that of hardness. 
Avanturine and its imitation, but largely 
the latter, are used for the cheaper kinds 
of jewelry, and were very popular in the 
United States some years ago. 

Cat's-Eye. 
The Hungarian, occidental, or quartz 
cat's-eye is found on the coast of Malabar, 
Ceylon, Hartz Mountains, and Bavaria. 



CROCIDOLITE. 1 1 5 

This stone is translucent to opaque, 
gray, green, brown, red, and the shadings 
of these colors, but usually a greenish- 
gray, with a mass of fine white lines in 
the centre, which give to the stone a 
chatoyant appearance. 

The cat's-eye is usually cut cabochon 
or carbuncle-shaped, and the lines (which 
are due to the fibres of asbestos) are kept 
in the centre of the stone, and play like 
the eye of a cat when the stone is moved. 

The quartz cat's-eye is easily distin- 
guished from the oriental of chrysoberyl 
cat's-eye, as it is softer and much lighter. 

CROCIDOLITE. 

Crocidolite or tiger-eye is a light-brown, 
brownish-yellow to dark-green, and green- 
ish-blue quartz, which has the same 
chatoyant qualities as the cat's-eye. When 
cut cabochon, the crocidolite is called 
tiger-eye. 

This beautiful mineral was very rare 



Il6 PRECIOUS STONES. 

some years ago, and good specimens were 
sold by the carat. 

Great quantities, however, have lately 
been found in South Africa, and although 
the finest pieces are still used for cameos 
and intaglios, many objects, such as paper- 
weights, umbrella handles, match-safes, 
etc., are now cut from this stone. 

Crocidolite is often artificially colored 
to very closely imitate some of the finest 
shades of the oriental cat's-eye. 

Heliotrope. 

Heliotrope or blood-stone, as this variety 
is commonly called, is a dark-green quartz, 
translucent to opaque, and covered with 
small red spots or blood-colored blotches, 
from which the stone derives the name of 
blood-stone. 

This stone has long been used for seal 
and signet purposes, and many fine in- 
taglios and cameos carved in blood-stone 
are in existence. 



CHR YSOPRA SE. II J 

Bucharia, Tartary, Siberia, East India, 
China, the island of Rum in the Hebrides, 
the United States, and Canada are some 
of the places where the heliotrope is 
found. 

Chrysoprase. 

The chrysoprase is an apple-green chal- 
cedony, sometimes olive- or whitish-green. 
It is translucent, scratches glass, and has 
the specific gravity of 2.56. 

The color is due to the presence of 
oxide of nickel. This stone is found 
principally in Silesia, but also in Siberia 
and the United States. 

Large pieces of chrysoprase are rare, 
and even the best specimens lose their 
color in course of time. 

Prase. 

A translucent, spotted leek-green, green 
quartz, which loses its polish on exposure 
to the air, is known as prase. 

This stone is found principally in the 
iron mines of Brietenbaum, Saxony, and 



Il8 PRECIOUS STONES. 

also in Brittany, the Tyrol, Scotland, 
Salzburg, Finland, and the United States. 
Prase is sometimes known commercially 
as " mother of emerald," and a greenish 
crystalline quartz is also often called prase. 

Plasma. 

Plasma is a dark grass-green quartz, 
feebly translucent, and is sometimes cov- 
ered with white or yellow spots. Plasma 
is somewhat lighter in weight than the 
heliotrope and does not take as fine a 
polish. 

This stone is found in India, China, and 
in the Black Forest, Germany. 

Chalcedony. 

Chalcedony is cloudy or translucent, 
white, yellowish-gray, blackish-brown, light 
to dark-blue, milky-white, and black. 

This quartz is sometimes nearly trans- 
parent, waxy in lustre, and in some varie- 
ties has a light gray and transparent base 
with dark cloudy spots. This last variety 



AGATES. II9 

is called " cloudy chalcedony. Another 
kind, with gray and white stripes alternat- 
ing, is known as chalcedonyx. 

Iceland, the Faroe Islands, Hiittenberg, 
Loben, Saxony, Hungary, Nubia, Nova 
Scotia, Oberstein, Ceylon, India, Siberia, 
Carinthia, the Hebrides, the United States, 
and Canada are places where chalcedony 
is found. 

Agates. 

Agate is an improved variety of chal- 
cedony and comprises the following kinds. 

Banded or ribbon agate, running in deli- 
cate parallel layers. 

Eye agate, forming concentric rings 
with a dark centre, giving the appearance 
of a human eye. 

Fortification agate, running in circular 
parallel zigzag lines like the walls of a 
fortress. 

Rainbow agate is a thin or concentric 
structure which when cut across and held 
towards the light shows an iridescence. 



120 PRECIOUS STONES. 

Moss agate, light-gray to white and 
translucent to opaque agates, display black 
tracings like fine moss or trees. Mocha or 
tree agates are covered with black, brown, 
or red figures, as of trees and plants. 

Beckite or silicified coral shells, silici- 
fied wood, wood agate, wood opal, cloudy 
agate, and agate jasper are some of the 
many varieties of this class. 

The common carnelians, blood-stones, 
and onyxes are usually counted among the 
agates. 

Uruguay, Brazil, Oberstein, Silesia, 
Surinam, India, Arabia, Saxony, Scotland, 
the United States, and Canada are the 
principal places where agates are found. 

Onyx or Agate Onyx. 

Onyx is a variety of chalcedony in bands 
or strata of white, gray, and black, trans- 
lucent to opaque, and generally found 
where agates abound. 

The layers or bands are in even planes, 
and the colors, white and black, white and 



ONYX OR AGATE ONYX. 121 

brown, or brown, white, and black, alter- 
nate. This stone is largely used for 
cameos, the base being usually of black or 
brown, and the engraved or upper part 
white- or cream-colored. 

When one or more layers are of car- 
nelian or sard, the stone is called sard- 
onyx. Sard is a rich brown color inclin- 
ing to red, and when held against the 
light shows a red hue. 

Onyx and sard-onyx are often artificially 
improved by boiling the stones in honey, 
oil, or sugar water, and then in sulphuric 
acid. The acid carbonizes the sugar or 
oil which the stone has absorbed and 
gives it a deeper color. 

For red, protosulphate of iron is added, 
and for a blue color to imitate lapis 
lazuli, yellow prussiate of potash is added 
to the protosulphate of iron. 

Only the porous parts of the stones, 
usually the dark parts, absorb the sugar 
or oil, and so aid the contrast of the 
colored with the white layers. 



122 PRECIOUS STONES. 

CARNELIAN. 

Carnelian is a clear red translucent 
chalcedony, and is usually of a gray or 
grayish-red color. Several weeks of ex- 
posure to the sun's rays and subsequent 
heating in earthen pots enhances and 
deepens the color. 

The brownish-red or dark-brown car- 
nelian is called sardoine or sard ; the 
blood-red to pink varieties, with an upper 
layer of white onyx, are called carnelian 
onyx, and the stones with a brown or sard 
base and a white top are called sard-onyx. 

Carnelians are sometimes of a yellowish- 
brown or yellow color, but red to brown 
are the principal colors. 

The secret of coloring agates was dis- 
covered in the early part of this century, 
and about the same time agates became 
scarce in Oberstein, while large finds were 
made in Brazil and Uruguay, especially of 
agates with red layers. This variety 
comes chiefly from Brazil. 

Besides Uruguay and Brazil, carnelian 



JASPER. 123 

is found in Arabia and India. The most 
beautiful specimens of intaglios are en- 
graved on sardoine, and some of the finest 
cameos extant are of sard and carnelian 
onyx. 

Jasper. 

Jasper is an impure opaque quartz, 
usually containing more iron than agate, 
and lacking the quality of translucency. 
Jasper occurs in red, brown, ochre-yellow, 
dark green, brownish-green, grayish-black, 
and grayish-blue ; sometimes containing 
bands or spots or quartz formations, and 
often found with regular zones or bands 
of various colors. 

Egyptian jasper or Egyptian pebbles 
are names given to varieties that are 
usually brown with inner bands of lighter 
hue, approaching cream in color, and 
sometimes having dark bands with spots 
or markings. 

Egyptian jasper is found near Grand 
Cairo, and other varieties are found in the 



124 PRECIOUS STONES. 

Urals, Saxony, Devonshire, Nova Scotia, 
Canada, and the United States. 

The specific gravity of jasper varies 
from 2.31 to 2.67; it scratches glass, but 
yields to rock-crystal. 

False Lapis. 

False lapis is jasper or agate artificially 
colored blue to imitate the true lapis. 
Lapis lazuli is softer than false lapis, being 
only 5 to 5.5 in hardness. 

Sappharine or siderite is a sapphire or 
sky-blue chalcedony occurring in Saltz- 
burg. 

Nicolo is a variety of onyx with a black 
or brown base and a band or layer of 
bluish-white on top. The upper layer is 
not flat, but convex, and is always thicker 
than the lower one. 

Hematite. 

Hematite was once largely used to en- 
grave upon, many of the ancient intaglios 
being on this mineral. It is now cut to 



OBSIDIAN. 125 

simulate black pearls, and is also used in 
the cheaper jewelry, both engraved and 
cut cabochon. 

Hematite has the hardness of 5.5 to 6.5, 
and specific gravity, 4.2 to 5.3 ; it is opaque, 
and shows a red streak when scratched. It 
is composed of: 

Iron, ... 70 
Oxygen, . . 30 

The colors of hematite are dark-steel 
gray to iron-black, and sometimes brown- 
ish- to blood-red. The lustre is highly 
metallic, with slight iridescence. 

The island of Elba, France, Switzer- 
land, Italy, Norway, Sweden, Bohemia, 
England, Brazil, Chili, Canada, Spain, and 
the United States are places where hema- 
tite is found. The Germans call this min- 
eral " blood-stone," and it is also known 
as specular iron ore and iron glance. 

Obsidian. 

Obsidian, or volcanic glass, does not oc- 
cupy a high position as a gem or as an 
ornamental stone, but its antiquity and 



126 PRECIOUS STONES. 

occasional use among the agates and semi- 
precious stones will justify its mention. 

This mineral is a melted lava, and con- 
sists of silex, alumina, and a little potassa, 
soda, and oxide of iron. Obsidian is 6 to 
7 in hardness, has a specific gravity of 
2.25 to 2.8, is sometimes transparent but 
mostly translucent to opaque, and is vit- 
reous to metallic in lustre. It is brittle and 
not easily attacked by acids. It melts be- 
fore the blow-pipe and takes a high polish. 

Obsidian comes from volcanoes, and is 
found in Iceland, TenerirTe, Lepare is- 
lands, Peru, Mexico, Sicily, and on all 
volcanoes. The color is velvety-black to 
gray, brown, greenish-black, yellow, blue, 
bottle-green, and white, seldom red, and 
often with black or yellow spots or 
veinings. 

Iceland agate lava, volcanic lava, and 
royal agate are all obsidian. 

Malachite. 
Malacnite although sometimes used for 
jewelry, is now more largely employed for 



MALACHITE. 12? 

mosaic work and ornamental vases, and is 
sufficiently costly and rare to be classed 
amongst the precious stones. 

Malachite is 3.5 to 4 in hardness ; has a 
specific gravity of 3.6 to 4; is translucent 
to opaque ; the lustre is vitreous to ada- 
mantine. It is attacked by acids, and 
melts before the blow-pipe. It is com- 
posed of: 

Carbonic acid ... 20. 
Protoxide of copper . 71.8 
Water 8. 



Malachite occurs in emerald or 
verdigris green color, sometimes in al- 
ternating stripes of different shades of 
green, and occasionally in leek- to black- 
ish-green. 

Malachite is found in Russia, France, 
the Tyrol, England, Scotland, Ireland, 
Germany, Africa, Chili, Australia, and the 
United States. 

The finest specimens are found in the 
Urals — a block three and a half feet square, 
being valued at $25,000 roubles. 



128 PRECIOUS STONES. 

Jet. 

The making of jet or mourning jewelry 
was once a very large industry in France 
and England, and even now Whitby jet is 
well known in commerce. 

Jet is a species of bituminous coal (can- 
nel coal) which can be cut with a knife. 
The hardness is I to 2.5 ; specific gravity, 
1.35 ; its lustre is not very high, and color 
pitch-black. 

It is found in England, France, Hesse, 
Spain, Italy, and Prussia. 

Amber. 

Amber is a fossil, and is not to be classed 
amongst minerals, but this material has 
always been used as an ornament, and a 
few notes will not be out of place here. 

This vegetable fossil, which has been 
known to the world for ages, the Greeks 
called electron. 

It is very light, having a specific gravity 
of 1.065 to 1.08, and is 2 to 2.5 in hardness. 



AMBER. 129 

The principal color is yellow, in various 
shades, sometimes running into white or 
reddish-brown and black. 

Amber is transparent to translucent, 
possesses single refraction, a resinous 
lustre to a high degree, becomes electric 
by rubbing, and burns readily before the 
blow-pipe. 

Amber when heated becomes soft and 
pliable. 

Amber is composed of: 



Carbon 


• • 79- 


Hydrogen 


. . 10.5 


Oxygen . . . 


. • 10.5 



Amber is imitated by gum copal, and 
even the insect enclosures which occur in 
real amber are copied. 

These imitations can be detected by 
placing the specimen in water or alcohol. 
This is also a good test for pieces of real 
amber that have been melted or glued 
together. 

Amber is thrown up by the sea, in riv- 
ers near the sea, or on the sea-shore, and 



130 PRECIOUS STONES. 

has been found in nearly all parts of the 
world. 

The Russian, Baltic, and Sicilian coasts 
have yielded the larger portion of the 
production, but supplies come also from 
Galizia, the Urals, Poland, China, and the 
United States. 

For ornamental purposes the faceted 
amber beads are largely used, but of late 
years these have been closely imitated 
in glass. 

Coral. 

Coral, although not a precious stone, 
has been largely used in jewelry, and as 
some of this beautiful substance is very 
valuable, a few words will not come amiss. 

Red or precious coral is the work of a 
family of zoophytes which live mostly in 
cavities of rock in the sea. 

These polyps build their homes at a 
depth of two to seven hundred feet 
under the surface of the sea, and although 
the single groups of coral are sometimes 



Coral. 131 

several feet long, the usual size is about 
twelve inches high, and about one inch 
at the thickest part of any single branch. 

Coral is usually red, and rarely white or 
black, while the pale rose-pink is the 
most esteemed color. 

Coral is mostly found at Calle, off the 
coast of Africa, but also on the coasts of 
Tunis, Algiers, Corsica, Barbary, Majorca, 
and Minorca. 

Coral fishing-vessels leave Italy the be- 
ginning of March and return from the 
African coast in October ; at one time as 
many as four hundred vessels were en- 
gaged in this industry. 



TABLE OF HARDNESS AND SPECIFIC 
GRAVITY. 







SPECIFIC 




HARDNESS. 










GRAVITY. 


Achroite .... 


7- —7-5 


3- 


— 3-1 


Alexandrite . 








8 


5 


3 


65 


-3-8 


Almandine . 








7 


5 


4 




— 4.2 


Almandite . 








7 


5 


4 




— 4.2 


Amber . . 








2 


— 2.5 


i 


065 


— 1.08 


Apatite . 








4 


5 — 5- 


2 


95 


— 3-25 


Axinite . 








6 


5 — 7- 


3 




— 3-3 


Beryl . . . 








7 


5-8. 


2 


67 


— 2.73 


Bobrowska garnet 






6 




3 


85 




Bohemian ' ' 






7 


5 


3 


69 


-3.78 


Brazilian emerald 






7 


— 7-5 


3 




— 3-1 


' ' sapphire 






7 


— 7-5 


3 




— 3-i 


Cachelong . . 






5 


5-6. 


2 




— 2.1 


Cat's-eye . . 






8 


5 


3 




-3-8 


Ceylon chrysolite 






7 


— 7-5 


3 




— 3-1 


" peridot. 






7 


— 7-5 


3 




— 3-1 


Chrysoberyl 






8 


5 


3 


65 


-3.8 


Chrysolite . . 






6 


5 — 7- 


3 


3 


— 3-5 


Chrysoprase 






7 




2 


56 




Cinnamon stone 






6 


5 


3 


5 


— 3-56 


Cyanite . . . 






5 


— 7- 


3 


45 


— 3-7 


Cymophane . 
Demantoide 






8 
6 


5 


3 
3 


65 

85 


-3-8 


Diamond . . 






IO 




3 


5 


-3-6 


Dichroite . . 






7 


— 7-5 


2 


56 


— 2.67 


Diopside . . . 






5 


— 6. 


2 


9 


— 3-5 


Emerald . 






7 


5-8. 


2 


67 


— 2.73 


Epidote . . . 






6 


— 7- 


3 


32 


— 3.5o 


Essonite . . . 






6 


5 


3 


5 


— 3.56 


Euclase . . . 






7 


5 


3 


1 




Fluor spar . . 






4 




3 


1 


— 3-2 



132 



HARDNESS AND SPECIFIC GRA VITY. 1 33 







SPECIFIC 




HARDNESS. 










GRAVITY. 


Garnet 


5 -8. 


3 15 


— 4-3 


Grossularite 


6 


5 


3 


5 


— 3-56 


Hematite .... 


5 


6 — 6.5 


4 


2 


— 5-3 


Hiddenite .... 


6 


5 — 7- 


3 


13 


— 3-19 


Hyacinth .... 


7 


5 


4 


4 


— 4-7 


Hydrophane . . . 


5 


5-6. 


2 




— 2.1 


Hypersthene . 


6 




3 


3 


— 3-4 


Idocrase 


6 


5 


3 


35 


— 3-45 


Indicolite .... 


7 


— 7-5 


3 




— 3-i 


Jacinth 


7 


5 


4 


4 


— 4-7 


Jargoon 


7 


5 


4 


4 


— 4-7 


Jasper 


7 




2 


3i 


— 2.67 


Jet 


2 


5 


1 


35 




Labrador .... 


6 




2 


62 


— 2.76 


' ' hornblende . 


6 




3 


3 


— 3-4 


Lapis lazuli .... 


5 


— 5-5 


2 


38 


— 2.42 


Malachite .... 


3 


5 — 4- 


3 


6 


— 4- 


Moonstone .... 


6 


-6.5 


2 


4 


— 2.6 


Obsidian .... 


6 


— 7- 


2 


25 


— 2.8 


Olivine 


6 


5 — 7- 


3 


3 


— 3-5 


Opal 


5 


5-6. 


2 




— 2.1 


Oriental amethyst . 


9 




3 


9 


— 4.1 


" aquamarine. 


9 




3 


9 


— 4.1 


" chrysolite . 


9 




3 


9 


— 4.1 


" emerald . 


9 




3 


9 


— 4.1 


" hyacinth. 


9 




3 


9 


— 4.1 


" topaz . 


9 




3 


9 


— 4.1 


Pearl 






2 


5 


— 2.7 


Peridot 


6 


5 — 7- 


3 


3 


— 3-5 


Phenacite .... 


7 


5-8. 


2 


96 


— 3- 


Pyrope 


7 


5 


3 


69 


-3.78 


Quartz 


7 




2 


5 


— 2.8 


" cat's-eye 


6 


-6.5 


2 


65 




Rose quartz .... 


7 




2 


65 


— 2.75 


Rubellite .... 


7 


— 7-5 


3 




— 3-1 


Ruby 


9 




3 


9 


— 4.1 


' ' cat's-eye . . 


9 




3 


9 


— 4.1 


Sapphire .... 


9 




3 


9 


— 4.1 


" cat's-eye . . 


9 




3 


9 


— 4.1 



134 



PRECIOUS STONES. 







SPECIFIC 




HARDNESS. 










GRAVITY. 


Siberite 


7- —7-5 


3- 


— 3-i 


Sphene . 






5- —5-5 


3 


4 


— 3.56 


Spinel . . 






8. 


3 


5 


-3-6 


Spodumene . 






6.5-7- 


3 


13 


— 3.19 


Star ruby 






9- 


3 


9 


— 4.1 


" sapphire 






9- 


3 


9 


— 4.1 


" topaz . 






9- 


3 


9 


— 4-1 


Sunstone 






6. -7. 


2 


56 


— 2.72 


Syrian garnet 






7-5 


4 




— 4.42 


Titanite . . 






5- —5-5 


3 


4 


— 3-56 


Topaz . . 






8. 


3 


4 


— 3-6 


Tourmaline . 






7- —7-5 


3 




— 3-1 


Turquois 






6. 


2 


6 


— 2.8 


Uwarowite . 






7-5 


3 


4i 


— 3-52 


Vesuvianite . 






6.5 


3 


35 


— 3-45 


Water sapphire 




7- —7-5 


2 


56 


— 2.67 



GENERAL INDEX. 



Achroite, 64 

Actinolite, 29 

Adularia, see moonstone 

Agate jasper, 120 

Agate onyx, see onyx 

Agate, see quartz, 106, 119, 122, 123, 124, 126 

Alexandrite, 8, 54, 56 

Almandine, 9, 30, 80 

Almandite, 29, 80 

Amazon stone, 17, 88, 91 

Amber, 17, 28 

American ruby, 80, 83 

Amethyst, 8, 9, 16, 17, 44, 49, 107, no, in 

Amethystine quartz, see amethyst 

Antimony, 29 

Apatite, 19, 87 

Aquamarine, 8, 16, 53 

Aquamarine chrysolite, 53 

Arizona ruby, 80, 83 

Asterias, see star sapphires 

Aurora red sapphire, see Oriental hyacinth 

Avanturine, 113, 114 

Avanturine felspar, see sunstone 

Axinite, 17, 102 

Balas ruby, 48 
Banded agate, 119 

135 



I36 PRECIOUS STONES. 

Beckite, 120 

Beryl, 14, 16, 17, 44, 50, 52, 53, 87 

Blood-stone, see heliotrope 

see hematite 
Bobrowska garnet, 80, 83 
Bohemian garnet, 80 82 

' ' diamond, see rock-crystal 

" topaz, see yellow quartz 
Bone turquois, 62 
Bort, 38 
Brazilian aquamarine, 85 

" emerald, 64, 67 

" ruby, 85 

" sapphire, 85 

" topaz, see topaz 
Bronzite, 30 

Cachelong, 69, 70 
Cairngorm, 107, in 
Calcite, 19 
Cameo, 8 

Cannel coal, see jet 
Cape garnet, 80, 83 
Cape ruby, 80, 83 
Carbon, 37 

Carbonate, see carbon 
Carbuncle, 80 83 
Carnelian, 17, 113, 123, 124 

" onyx, 122 

Cat's-eye, corundum, 8, 54, 57, 115, 116 

" quartz, 18, 58, 107, 113, 114, 115 
Ceylon cat's-eye, see corundum cat's-eye 

" chrysolite, 64, 79 

" opal, see moonstone 

" peridot. 64 



GENERAL INDEX. 1 37 

Ceylonite, 47 

Chalcedonyx, see chalcedony 

Chalcedony, 8, 9, 16, 17, 113, 118, 119, 120, 122, 124 

Chrysoberyl 16, 17, 45, 54, 56, 57, 79 

Chrysolite, 17, 30, 53, 58, 78, 87, 99, 107 

Chrysoprase, 17, 107, 113, 117 

Cinnamon stone, see grossularite 

Cleavage, 10 

Cloudy agate, 120 

" chalcedony, see chalcedony 
Colors, 16 
Coral, 130 

Cordierite, see dichroite 
Corundum, 9, 17, 39, 45, 47, 48, 49 
Crocidolite, 5, 18, 113, 115 
Crystallization, 10 
Cutting, 32 
Cyanite, 17, 92 
Cymophane, 54, 56, 57 

Decimal system, 28 

Demantoide, see Bobrowska garnet 

Diamond, 9, 11, 12, 14, 15, 17, 18, 20, 31, 32, 33, 35, 

40, 41, 49, 51, 52, 60, 75, 101, 109 
Dichroiscope, 14 
Dichroite, 97 
Diopside, 103 

Egyptian jasper, 123 

" pebbles, see Egyptian jasper 
Electricity, 31 

Emerald, 8, 9, 16, 17, 18, 31, 44, 51, 87, 95, 107 
Epidote, 17, 101 
Essonite, see grossularite 



i$& PRECIOUS STOJSTES. 

Euclase, 99 
Eye agate, 119 

False emerald, see fluor spar 

" lapis, 124 

" ruby, see fluor spar 

' ' topaz, see fluor spar and yellow quartz 
Fancy sapphires, 44 
Felspar, 20, 88, 91 
Fish-eye, see moonstone 
Flint, 113 

Fluorspar, 17, 19, 31, 104 
Fortification agate, 119 
Fossil turquois, 63 
Fracture, 11 
Fusibility, 28 

Garnet, 12, 14, 15, 17, 21, 32, 42, 53, 64, 107 

Girasol, 46 

Glass, 15 

Golden beryl, 54 

Goldstone, see avanturine 

Goutte d'eau, 85 

Green felspar, see Amazon stone 

" garnet, 80, 99 

" sapphire, see Oriental emerald 
Greenish-yellow sapphire, see Oriental chrysolite 
Grossularite, 30, 80, 82 

Hair-stone, see cairngorm 

Heliotrope, 113, 116, 118, 120 

Hematite, 18, 124 

Hiddenite, 95 

Hornstone, 113 

Hungarian cat's-eye, see quartz cat's-eye 



GENERAL INDEX, 1 39 

Hyacinth, 42, 58, 59 
Hydrophane, 69, 70 
Hypersthene, 105 

Iceland lava, see obsidian 

" spar, 14 
Idocrase, 17, 98 
Indian topaz, see yellow quartz 
Indicolite, 64, 67 
Intaglio, 8 
Iolite, see dichroite 
Iridescent quartz, see rose quartz 

Jacinth, 58, 59, 82 
Jargoon, 58, 59 
Jaspar, 17, 106, 113, 123, 124 
Jet, 16, 128 

Labrador, 16, 88, 91 

' ' hornblende, see hypersthene 
Labradorite, see Labrador 
Labrador spar, see Labrador 
Lake George diamond, see rock-crystal 
Lapis lazuli, 17, 93, 124 
Lava, see obsidian 

Light-green sapphire, see Oriental aquamarine 
Love arrows, see cairngorm 
Lustre, 17 

Magnetism, 30 

Malachite, 17, 127 

Mica, 11 

Mineral turquois, 61, 62 

Mocha agate, 120 

Moonstone, 17, 38, 91, 109, 112 



140 PRECIOUS STONES. 

Moss agate, 120 

Mother of emerald, see prase 



Natrolite, 29 

Needle-stone, see cairngorm 
Nicolo, 124 



Obsidian, 10, 16, 125 
Occidental cat's-eye, see quartz cat's-eye 
" diamond, see rock-crystal 
' ' topaz, see yellow quartz 
" turquois, 62 
Odontolite, 17, 62 
(Eil de bceuf, see Labrador 
Oligoclase, see sun-stone 
Olivine, 17, 18, 53, 78, 84 
Onyx, 8, 106, 107, 113, 120, 124 
Opal, 8, 9, 10, 16, 17, 18, 30, 69, 100, 102, 107 
" common, see opal 
" fire, " " 

" noble, " " 
Opaline felspar, see Labrador 
Oriental amethyst, 39, 44 
" aquamarine, 39, 44 
" chrysolite, 39, 44 ; see also chrysoberyl 
" emerald, 39, 44, 51 
" hyacinth, 39, 44 
" opal, see opal 

topaz, 39, 44, 87 
" turquois, 61 
Orthoclase, 29, 87 
Orthose, see moonstone 
Ox-eye, see Labrador 



GENERAL INDEX. 141 



Pearl, 71 

" baroque, 74 

" black, 73, 124 

" bouton, 74 

" pink, 77 
Pebble diamond, see rock-crystal 
Peridot, 16, 78 
Persian turquois, 62 
Phenacite, 101 
Phosphorescence, 31 
Plasma, 113, 118 
Pleiochroism, 14 
Pleonast, 47 
Polarization of light, 13 
Polishing, 32 
Prase, 17, 113, 117, 118 
Precious schorl, see tourmaline 
Purple sapphire, see Oriental amethyst 
Pyrope, 30, 80, 82 

Quartz, 9, 16, 20, 22, 42, 50, 106, 123 
" cat's-eye, see cat's-eye quartz 

Rainbow agate, 119 
" quartz, 112 
Reconstructed rubies, 43 

turquois, 64 
Red quartz, see quartz 

" sapphire, see ruby 
Refraction, 12 
Rhinestone, see rock-crystal 
Ribbon agate, 119 
Rock-crystal, 17, 38, 91, 109, 112 

" salt, 11, 19 
Rose quartz, 17, 113 



142 PRECIOUS STONES. 

Rose topaz, see topaz 

Royal agate, see obsidian 

Rubellite, 64, 65 

Rubicelle, 48 

Ruby, 14, 15, 16, 17, 18, 2i, 26, 32, 37, 39, 40, 53, 64, 

107 
Ruby, cat's-eye, 39, 46 
" spinel, see spinel 

Saganite, see cairngorm 

Saphir d'eau, see dichroite 

Sappare, see cyanite 

Sapphire, 16, 17, 20, 21, 37, 38, 39, 41, 42, 43, 51, 52, 

93, 98 
Sapphire, cat's-eye, 39, 46 
Sapphirine, 48, see false lapis 
Sard, 121, 122 
Sardoine, see sara 
Sardonyx, 121, 122 
Saxony topaz, 85 
Siberian aquamarine, 53 

" topaz, 85 
Siberite, 64 
Siderite, see false lapis 
Silicified coral shells, see beckite 

" wood, 120 
Slave's diamond, see topaz 
Smoky-quartz, see cairngorm 

" topaz, 16, 17 
Spanish topaz, see yellow quartz 
Specific gravity, 21 
Sphene, 100 

Spinel, 12, 14, 15, 17, 18, 21, 42,46 
Spodumene, 95, 96 
Star ruby, 39, 45 

I 



GENERAL INDEX I43 

Star sapphire, 39, 45 

" topaz, 39, 45 
Streak, 18 

Sunstone, 46, 88, 89, 90 
Syrian garnet, 80 

Talc, 19 

Titanite, see sphene 

Tiger-eye, see crocidolite 

Topaz, 8, 9, 16, 17, 20, 31, 32, 38, 42, 49, 50, 58, 84, 

107, in 
Tourmaline, 13, 16, 17, 21, 32, 42, 53, 64, 107 
Transparency, 30 
Tree agate, see Mocha agate 
Turquois, 9, 10, 17, 18, 30, 60, 107 

Uwarowite, 80, 83 

Venus hair-stone, see cairngorm 
Vermeille, 80, 83 
Vesuvianite, see idocrase 
Volcanic glass, see obsidian 
" lava, " " 

Water opal, see moonstone 

" sapphire, see dichroite 
Weight, 27 

White spinel, see spinel 
Wood agate, 120 

" opal, 120 

Yellow quartz, 111 

" sapphire, see Oriental topaz 

Zircon, 9, 16, 17, 18, 38, 49, 58 



w 






